Process for forming cobalt-containing materials

ABSTRACT

Embodiments of the invention described herein generally provide methods and apparatuses for forming cobalt silicide layers, metallic cobalt layers, and other cobalt-containing materials. In one embodiment, a method for forming a cobalt silicide containing material on a substrate is provided which includes exposing a substrate to at least one preclean process to expose a silicon-containing surface, depositing a cobalt silicide material on the silicon-containing surface, depositing a metallic cobalt material on the cobalt silicide material, and depositing a metallic contact material on the substrate. In another embodiment, a method includes exposing a substrate to at least one preclean process to expose a silicon-containing surface, depositing a cobalt silicide material on the silicon-containing surface, expose the substrate to an annealing process, depositing a barrier material on the cobalt silicide material, and depositing a metallic contact material on the barrier material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/014,656 filed Jan. 26, 2011 (APPM/00547.C5), which is a continuationof U.S. patent application Ser. No. 11/733,929 (APPM/005547.P2), filedApr. 11, 2007, which claims benefit of U.S. Patent Application No.60/791,366 (APPM/010948L), filed Apr. 11, 2006, and U.S. PatentApplication No. 60/863,939 (APPM/010948L.02), filed Nov. 1, 2006. Theabove-referenced patent applications are herein incorporated byreference.

This application is related to U.S. patent application Ser. No.11/456,073 (APPM/005547.C2), filed Jul. 6, 2006, now issued as U.S. Pat.No. 7,416,979, which is a continuation of U.S. patent application Ser.No. 10/845,970 (APPM/005547.C1), filed May 14, 2004, and now abandoned,which is a continuation of U.S. patent application Ser. No. 10/044,412(APPM/005547.P1), filed Jan. 9, 2002, and issued as U.S. Pat. No.6,740,585, which is a continuation-in part of U.S. patent applicationSer. No. 09/916,234 (APPM/005547), filed Jul. 25, 2001, and nowabandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the fabrication of semiconductor and otherelectronic devices and to methods for the deposition of materials (e.g.,cobalt containing) on a substrate.

2. Description of the Related Art

Recent improvements in circuitry of ultra-large scale integration (ULSI)on semiconductor substrates indicate that future generations ofsemiconductor devices will require sub-quarter micron multi-levelmetallization. The multilevel interconnects that lie at the heart ofthis technology require planarization of interconnect features formed inhigh aspect ratio apertures, including contacts, vias, lines and otherfeatures. Reliable formation of these interconnect features is veryimportant to the success of ULSI and to the continued effort to increasecircuit density and quality on individual substrates and die as featuresdecrease below 0.13 μm in size.

ULSI circuits include metal oxide semiconductor (MOS) devices, such ascomplementary metal oxide semiconductor (CMOS) field effect transistors(FETs). The transistors can include semiconductor gates disposed betweensource and drain regions. In the formation of integrated circuitstructures, and particularly in the formation of MOS devices usingpolysilicon gate electrodes, it has become the practice to provide ametal silicide layer over the polysilicon gate electrode, and over thesource and drain regions of the silicon substrate, to facilitate lowerresistance and improve device performance by electrically connecting thesource and drain regions to metal interconnects.

One important processing technique currently used in CMOS processingtechnology is the Self-Aligned Silicidation (salicide) process ofrefractory metals such as titanium and cobalt. In a salicide processusing cobalt, for example, the source and drain and polysilicon gateresistances are reduced by forming a high conductivity overlayer and thecontact resistance is reduced by increasing the effective contact areaof the source and drain with subsequently formed metal interconnects.Salicide processing technology seeks to exploit the principle that arefractory metal such as cobalt deposited on a patterned siliconsubstrate will selectively react with exposed silicon under specificprocessing conditions, and will not react with adjacent materials, suchas silicon oxide material.

For example, a layer of cobalt is sputtered onto silicon, typicallypatterned on a substrate surface, and then subjected to a thermalannealing process to form cobalt silicide. Unreacted cobalt, such ascobalt deposited outside the patterned silicon or on a protective layerof silicon oxide, can thereafter be selectively etched away. Theselective etching of cobalt silicide will result in maskless,self-aligned formation of a low-resistivity refractory metal silicide insource, drain, and polysilicon gate regions formed on the substratesurface and in interconnecting conductors of the semiconductor device.After the etch process, further processing of the substrate may occur,such as additional thermal annealing, which may be used to furtherreduce the sheet resistance of the silicide material and completeformation of cobalt silicide.

However, it has been difficult to integrate cobalt silicide processesinto conventional manufacturing equipment. Current processing systemsperforming cobalt silicide processes require transfer of the substratebetween separate chambers for the deposition and annealing processsteps. Transfer between chambers may expose the substrate tocontamination and potential oxidation of silicon or cobalt deposited onthe substrate surface.

Oxide formation on the surface of the substrate can result in increasingthe resistance of silicide layers as well as reducing the reliability ofthe overall circuit. For example, oxidation of the deposited cobaltmaterial may result in cobalt agglomeration and irregular growth of thecobalt silicide layer. The agglomeration and irregular growth of thecobalt silicide layer may result in device malformation, such as sourceand drain electrodes having different thicknesses and surface areas.Additionally, excess cobalt silicide growth on substrate surface mayform conductive paths between devices, which may result in shortcircuits and device failure.

One solution to limiting cobalt and silicon contamination has been tosputter a capping film of titanium and/or titanium nitride on the cobaltand silicon film prior to transferring the substrate between processingsystems. The capping film is then removed after annealing the substrateand prior to further processing of the substrate. However, the additionof titanium and titanium nitride deposition and removal processesincreases the number of processing steps required for silicideformation, thereby reducing process efficiency, increasing processingcomplexity, and reducing substrate throughput.

ULSI circuits also include the formation of interconnects or contactsbetween conductive layers, such as the cobalt silicide layer describedabove and a copper feature. Interconnects or contacts generally comprisea feature definition formed in a dielectric material, such as siliconoxide, a barrier layer deposited on the feature definition, and a metallayer fill or “plug” of the feature definition. Titanium and titaniumnitride films have been used as barrier layer material for the metallayer, such as tungsten, and the films are generally deposited by aphysical vapor deposition technique. However, deposition of titaniumover silicon surfaces presents the problem of titanium silicideformation.

Titanium silicide has been observed to agglomerate, which detrimentallyaffects subsequently deposited materials. Also, titanium silicideexhibits a radical increase in sheet resistance as feature sizesdecrease below 0.17 μm, which detrimentally affects the conductance ofthe feature being formed. Further, titanium silicide has an insufficientthermal stability during processing of the substrate at temperatures ofabout 400° C. or higher, which can result in interlayer diffusion anddetrimentally affect device performance.

Additionally, titanium and titanium nitride PVD deposition often occurat extremely low processing pressures, i.e., less than about 5×10⁻³Torr, compared with CVD deposition of materials such as tungsten, whichmay be deposited as high as about 300 Torr. This results in difficultintegration of PVD and CVD processes in the same system. This hasresulted in many manufactures using separate systems for the PVDtitanium and titanium nitride deposition and the CVD tungstendeposition. The increase in the number of systems results in increasedproduction costs, increased production times, and exposes the processedsubstrate to contamination when transferred between systems.

Therefore, there is a need for a method and apparatus for formingbarrier layers and silicide materials on a substrate while reducingprocessing complexity and improving processing efficiency andthroughput.

SUMMARY OF THE INVENTION

Embodiments of the invention described herein generally provide methodsand apparatuses for forming cobalt silicide layers, metallic cobaltlayers, and other cobalt-containing layers using deposition processes,annealing processes, or combinations thereof. In one embodiment, amethod for forming a cobalt silicide containing material on a substrateis provided which includes exposing a substrate to at least one precleanprocess to expose a silicon-containing surface, depositing a cobaltsilicide material on the silicon-containing surface, depositing ametallic cobalt material on the cobalt silicide material, and depositinga metallic contact material on the substrate. In another embodiment, amethod for forming a cobalt silicide containing material on a substrateis provided which includes exposing a substrate to at least one precleanprocess to expose a silicon-containing surface, depositing a cobaltsilicide material on the silicon-containing surface, expose thesubstrate to an annealing process, depositing a barrier material on thecobalt silicide material, and depositing a metallic contact material onthe barrier material.

The cobalt silicide material may be deposited by exposing the substrateto a cobalt precursor and a silicon precursor during a chemical vapordeposition process or an atomic layer deposition process. The cobaltsilicide material may contain a silicon/cobalt atomic ratio of greaterthan 0.5, such as within a range from about 1 to about 2. The metalliccontact material may contain tungsten, copper, aluminum, alloys thereof,or combinations thereof. In one example, the deposition of the metalliccontact material includes forming a seed layer and forming a bulk layerthereon. The seed layer and the bulk layer may each contain tungsten. Inother examples, a barrier material may be deposited on the metalliccobalt material and the metallic contact material is deposited on thebarrier layer. The barrier material may contain cobalt, tantalum,tantalum nitride, titanium, titanium nitride, tungsten, tungstennitride, alloys thereof, or derivatives thereof.

In another embodiment, the cobalt precursor may be tricarbonyl allylcobalt, cyclopentadienyl cobalt bis(carbonyl), methylcyclopentadienylcobalt bis(carbonyl), ethylcyclopentadienyl cobalt bis(carbonyl),pentmethylcyclopentadienyl cobalt bis(carbonyl), dicobaltocta(carbonyl), nitrosyl cobalt tris(carbonyl),bis(cyclopentadienyl)cobalt, (cyclopentadienyl)cobalt (cyclohexadienyl),cyclopentadienyl cobalt (1,3-hexadienyl), (cyclobutadienyl)cobalt(cyclopentadienyl), bis(methylcyclopentadienyl)cobalt,(cyclopentadienyl)cobalt (5-methylcyclopentadienyl), bis(ethylene)cobalt(pentamethylcyclopentadienyl), derivatives thereof, complexes thereof,plasmas thereof, or combinations thereof. In one example, the cobaltprecursor is cyclopentadienyl cobalt bis(carbonyl). In other examples,the cobalt precursor may have the general chemical formula(CO)_(x)Co_(y)L_(z), wherein X is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or12; Y is 1, 2, 3, 4, or 5; Z is 1, 2, 3, 4, 5, 6, 7, or 8; and L is aligand independently selected from the group consisting ofcyclopentadienyl, alkylcyclopentadienyl, methylcyclopentadienyl,pentamethylcyclopentadienyl, pentadienyl, alkylpentadienyl,cyclobutadienyl, butadienyl, allyl, ethylene, propylene, alkenes,dialkenes, alkynes, nitrosyl, ammonia, derivatives thereof, orcombinations thereof. The silicon precursor may be silane, disilane,derivatives thereof, plasmas thereof, or combinations thereof.

In another example, the substrate is heated to a temperature of at least100° C. during the chemical vapor deposition process or the atomic layerdeposition process, preferably, to a temperature within a range fromabout 300° C. to about 400° C. The substrate may be heated to atemperature of at least about 600° C. within an annealing chamber duringthe annealing process. The cobalt silicide material may be exposed to aplasma process prior to depositing the metallic cobalt material. Inother example, the plasma process may contain hydrogen gas and theplasma may be ignited by a radio frequency of about 13.56 MHz.

In another embodiment, the cobalt silicide material may be depositedduring the atomic layer deposition process by conducting a depositioncycle to deposit a cobalt silicide layer, and repeating the depositioncycle to form a plurality of the cobalt silicide layers, wherein thedeposition cycle contains exposing the substrate to a silicon-containingreducing gas comprising the silicon precursor while sequentiallyexposing the substrate to the cobalt precursor and a plasma (e.g.,hydrogen plasma). In some examples, the substrate, the cobalt silicidematerial, the metallic cobalt material, or the barrier material may beexposed to the silicon-containing reducing gas during a pre-soak processor a post-soak process. The substrate may be exposed to a plasmatreatment during the pre-soak process or the post-soak process. In someexamples, the cobalt silicide material and the metallic cobalt materialmay be deposited in the same processing chamber.

In another embodiment, a method for forming a metallic silicidecontaining material on a substrate is provided which includes exposing asubstrate to at least one preclean process to expose asilicon-containing surface, depositing a metallic silicide material onthe silicon-containing surface during a chemical vapor depositionprocess or an atomic layer deposition process, expose the substrate toan annealing process, depositing a barrier material on the metallicsilicide material, and depositing a tungsten contact material on thebarrier material. The metallic silicide material may contain at leastone element of cobalt, nickel, platinum, palladium, rhodium, alloysthereof, or combinations thereof. The examples provide that thesubstrate, the metallic silicide material, or the barrier material maybe exposed to a silicon-containing reducing gas during a pre-soakprocess or a post-soak process. In some examples, the substrate may beexposed to a plasma treatment during the pre-soak process or thepost-soak process.

In another embodiment, a cobalt silicide layer is deposited on asilicon-containing substrate surface during a vapor deposition processand a metallic cobalt layer is deposited thereon by another vapordeposition process. In one aspect, the cobalt silicide layer isdeposited by co-flowing a cobalt precursor and a silicon precursorduring a CVD process. Thereafter, the flow of silicon precursor into theCVD chamber is stopped while the flow of the cobalt precursor iscontinued and a metallic cobalt material is deposited on the cobaltsilicide material. A reductant, such as hydrogen, may be co-flowed withthe cobalt precursor. Alternatively, the cobalt precursor may be reducedby a thermal decomposition process or a plasma process during the CVDprocess.

In another embodiment, a metallic cobalt layer is deposited on thesilicon-containing substrate surface, the substrate is exposed to anannealing process to form a cobalt silicide layer by a salicide process,and a second metallic cobalt layer is deposited thereon.

A substrate may be exposed to at least one preclean process duringembodiments described herein. In one example, the preclean processincludes exposing the substrate to a preclean gas containing an argonplasma, such as a Ar+ PC. In another example, the preclean processincludes exposing the substrate to a plasma etch process for removingnative oxides on the substrate surface using an ammonia (NH₃) andnitrogen trifluoride (NF₃) gas mixture performed within a plasma etchprocessing chamber, such as the SICONI™ preclean process, available fromApplied Materials, Inc., located in Santa Clara, Calif. In anotherexample, the substrate is exposed to a wet clean process, such as abuffered oxide etch (BOE) process, a SC1 process, a SC2 process, or aHF-last process.

In one embodiment, a cobalt silicide material is deposited on thesubstrate during an ALD process or a CVD process and a metallic cobaltmaterial is deposited on the cobalt silicide material during another ALDprocess or another CVD process. The substrate may be exposed to anannealing process in the deposition chamber or in an annealing chamber.A metallic contact material (e.g., W, Cu, Al, or alloys thereof) isdeposited on the substrate and the substrate may be exposed to aplanarization process. The metallic contact material may be deposited ina single deposition process or in several deposition processes, such asto form a seed layer, a bulk layer, a fill layer, or combinationsthereof. In another embodiment, a barrier layer may be deposited on themetallic cobalt material prior to depositing the metallic contactmaterial.

In one example, the cobalt silicide material and the metallic cobaltmaterial are deposited in the same ALD chamber or CVD chamber. Inanother example, the cobalt silicide material and the metallic cobaltmaterial are deposited and the substrate is annealed in the same ALDchamber or CVD chamber. In another example, the cobalt silicide materialand the metallic cobalt material are deposited in the same ALD chamberor CVD chamber and the substrate is annealed in an annealing chamber. Inanother example, the cobalt silicide material and the metallic cobaltmaterial are deposited in different ALD chambers or CVD chambers and thesubstrate is annealed in an annealing chamber. In another example, thecobalt silicide material is deposited in an ALD chamber or a CVDchamber, the substrate is annealed in an annealing chamber, and themetallic cobalt material is deposited in another ALD chamber or CVDchamber. In another example, the cobalt silicide material is depositedin an ALD chamber or a CVD chamber, the metallic cobalt material isdeposited in another ALD chamber or CVD chamber, and the substrate isannealed in an annealing chamber.

In other embodiments, the cobalt silicide material and the metalliccobalt material are deposited in the same ALD chamber or CVD chamber,the metallic contact material is deposited on the metallic cobaltmaterial, the substrate is exposed to a planarization process, and thesubstrate is annealed in an annealing chamber. In another example, thecobalt silicide material and the metallic cobalt material are depositedin the same ALD chamber or CVD chamber, the metallic contact material isdeposited on the metallic cobalt material, the substrate is annealed inan annealing chamber, and the substrate is exposed to a planarizationprocess.

In another embodiment, a first metallic cobalt material is deposited ona silicon-containing surface of the substrate within an ALD chamber or aCVD chamber. The substrate is exposed to an annealing process within theALD or CVD chamber to form a cobalt silicide material by a salicideprocess. Subsequently, a second metallic cobalt material is deposited onthe cobalt silicide material within a different ALD or CVD chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the inventioncan be understood in detail, a more particular description of theinvention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 illustrates a schematic top view of an integrated multi-chamberapparatus as described by embodiments herein;

FIG. 2 illustrates a schematic top view of another integratedmulti-chamber apparatus as described by embodiments herein;

FIG. 3 illustrates a cross-sectional view of one embodiment of asputtering chamber included within the invention;

FIG. 4 depicts an expanded view of FIG. 3 including the upper area ofthe shields near the target;

FIG. 5 illustrates a plan view of one embodiment of a ring collimator;

FIG. 6 illustrates a partial plan view of one embodiment of a honeycombcollimator;

FIG. 7A illustrates a cross-sectional view of one embodiment of apedestal for annealing a substrate;

FIG. 7B illustrates a cross-sectional view of another embodiment of apedestal for annealing a substrate;

FIGS. 8A-8C depict schematic cross-sectional views of a substrate duringdifferent stages of fabrication as described by an embodiment herein;

FIG. 9 depicts a schematic cross-sectional of another substratecontaining a silicide material used as a contact with a transistor asdescribed by an embodiment herein;

FIG. 10 shows a flow-chart of an integrated process described by anembodiment herein;

FIG. 11 shows a flow-chart of another integrated process described byembodiments herein;

FIG. 12 shows a flow-chart of another integrated process described byembodiments herein;

FIG. 13 shows a flow-chart of another integrated process described byembodiments herein;

FIG. 14 shows a flow-chart of another integrated process described byembodiments herein;

FIG. 15 shows a flow-chart of another integrated process described byembodiments herein;

FIG. 16 shows a flow-chart of another integrated process described byembodiments herein;

FIGS. 17A-17I depict schematic cross-sectional views of a substrateduring different stages of fabrication as described by embodimentsherein;

FIG. 18 illustrates a schematic top view of an integrated multi-chamberapparatus as described by embodiments herein;

FIG. 19 shows a flow-chart of another integrated process described byembodiments herein;

FIG. 20 shows a flow-chart of an integrated process described by anotherembodiment herein;

FIG. 21 shows a flow-chart of another integrated process described byembodiments herein;

FIG. 22 shows a flow-chart of a cobalt silicide deposition processdescribed by an embodiment herein;

FIG. 23 shows a graph of chemical precursor sequences for a cobaltsilicide deposition process described by an embodiment herein;

FIG. 24 shows a flow-chart of an integrated process described by anotherembodiment herein;

FIGS. 25A-25B depict schematic cross-sectional views of a substrateduring different stages during a cobalt silicide deposition processdescribed by an embodiment herein; and

FIG. 26 shows a flow-chart of an integrated process described by anotherembodiment herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the invention described herein provide methods andapparatus for forming cobalt silicide materials, metallic cobaltmaterials, and other cobalt-containing materials within a depositionchamber. A processing system for depositing and forming material on asubstrate may contain at least one preclean chamber, at least onedeposition chamber, and at least one annealing chamber. Generally, thesystem contains at least one CVD chamber and/or at least one ALDchamber. A silicon-containing surface is exposed on the substrate duringa preclean process. Subsequently, in one embodiment, a cobalt silicidematerial is deposited, a metallic cobalt material is deposited, anoptional barrier layer may be deposited, and a metallic contact materialis deposited on the substrate. The substrate is exposed to at least oneannealing process prior to, during, subsequently to any of thedeposition processes, as well as, subsequent a planarization process.

FIG. 1 shows an integrated multi-chamber substrate processing systemsuitable for performing at least one embodiment of the deposition andannealing processes described herein. The deposition and annealingprocesses may be performed in a multi-chamber processing system orcluster tool having at least one ALD chamber, at least one CVD chamber,at least one PVD chamber, or at least one annealing chamber disposedthereon. A processing platform that may be used to during processesdescribed herein is an ENDURA® processing platform commerciallyavailable from Applied Materials, Inc., located in Santa Clara, Calif.

FIG. 1 is a schematic top view of one embodiment of a processingplatform system 35 including two transfer chambers 48, 50, transferrobots 49, 51, disposed within transfer chambers 48, 50 respectfully,and a plurality of processing chambers 36, 38, 40, 41, 42 and 43,disposed on the two transfer chambers 48, 50. The first transfer chamber48 and the second transfer chamber 50 are separated by pass-throughchambers 52, which may comprise cool-down or pre-heating chambers.Pass-through chambers 52 also may be pumped down or ventilated duringsubstrate handling when the first transfer chamber 48 and the secondtransfer chamber 50 operate at different pressures. For example, thefirst transfer chamber 48 may operate at a pressure within a range fromabout 100 milliTorr to about 5 Torr, such as about 400 milliTorr, andthe second transfer chamber 50 may operate at a pressure within a rangefrom about 1×10⁻⁵ Torr to about 1×10⁻⁸ Torr, such as about 1×10⁻⁷ Torr.Processing platform system 35 is automated by programming amicroprocessor controller 54.

The first transfer chamber 48 is coupled with two degas chambers 44, twoload lock chambers 46, a reactive preclean chamber 42 and chamber 36,such as an ALD process chamber or a PVD chamber, preferably a long throwphysical vapor deposition (PVD) chamber and the pass-through chambers52. The preclean chamber 42 may be a PreClean II chamber, commerciallyavailable from Applied Materials, Inc., of Santa Clara, Calif.Substrates (not shown) are loaded into processing platform system 35through load-lock chambers 46. Thereafter, the substrates aresequentially degassed and cleaned in degas chambers 44 and the precleanchamber 42, respectively. The transfer robot 49 moves the substratebetween the degas chambers 44 and the preclean chamber 42. The substratemay then be transferred into chamber 36, such as the ALD chamber or thelong throw PVD chamber for deposition of a material thereon.

The second transfer chamber 50 is coupled to a cluster of processchambers 38, 40, 41, and 43. In one example, chambers 38 and 40 may beALD chambers for depositing materials, such as cobalt silicide, metalliccobalt, or tungsten, as desired by the operator. In another example,chambers 38 and 40 may be CVD chambers for depositing materials, such astungsten, as desired by the operator. An example of a suitable CVDchamber includes WXZ™ chambers, commercially available from AppliedMaterials, Inc., located in Santa Clara, Calif. The CVD chambers may beadapted to deposit materials by ALD techniques as well as byconventional CVD techniques. Chambers 41 and 43 may be Rapid ThermalAnnealing (RTA) chambers, or Rapid Thermal Process (RTP) chambers, thatcan anneal substrates at low or extremely low pressures. An example ofan RTA chamber is a RADIANCE® chamber, commercially available fromApplied Materials, Inc., Santa Clara, Calif. Alternatively, the chambers41 and 43 may be WXZ™ deposition chambers capable of performing hightemperature CVD deposition, annealing processes, or in situ depositionand annealing processes. The PVD processed substrates are moved fromtransfer chamber 48 into transfer chamber 50 via pass-through chambers52. Thereafter, transfer robot 51 moves the substrates between one ormore of the process chambers 38, 40, 41, and 43 for material depositionand annealing as required for processing.

RTA chambers (not shown) may also be disposed on the first transferchamber 48 of processing platform system 35 to provide post depositionannealing processes prior to substrate removal from processing platformsystem 35 or transfer to the second transfer chamber 50.

While not shown, a plurality of vacuum pumps is disposed in fluidcommunication with each transfer chamber and each of the processingchambers to independently regulate pressures in the respective chambers.The pumps may establish a vacuum gradient of increasing pressure acrossthe apparatus from the load lock chamber to the processing chambers.

Alternatively, a plasma etch chamber, such as a DPS® (decoupled plasmasource) chamber manufactured by Applied Materials, Inc., of Santa Clara,Calif., may be coupled to processing platform system 35 or in a separateprocessing system for etching the substrate surface to remove unreactedmetal after PVD metal deposition and/or annealing of the depositedmetal. For example in forming cobalt silicide from cobalt and siliconmaterial by an annealing process, the etch chamber may be used to removeunreacted cobalt material from the substrate surface. The invention alsocontemplates the use of other etch processes and apparatus, such as awet etch chamber, used in conjunction with the process and apparatusdescribed herein.

FIG. 2 is a schematic top view of another embodiment of an integratedmulti-chamber substrate processing system 35 suitable for performing atleast one embodiment of the ALD, CVD, PVD, or annealing processesdescribed herein. In one embodiment, the first transfer chamber 48 iscoupled to a cluster of process chambers 38, 40, 41, and 43, two loadlock chambers 46, and pass-through chambers 52. Chambers 41 and 43 maybe a RTA chambers that can anneal substrates at low or extremely lowpressures, such as the RADIANCE® chamber, and chambers 38 and 40 are ALDchambers or CVD chambers, such as WXZ™ chambers. The first transferchamber 48 may operate at a pressure within a range from about 1×10⁻⁵Torr to about 1×10⁻⁸ Torr, such as about 1×10⁻⁷ Torr, and the secondtransfer chamber 50 may operate at a pressure within a range from about100 milliTorr to about 5 Torr, such as about 400 milliTorr.

Alternatively, chambers 41 and 43 may be WXZ™ chambers capable ofperforming high temperature CVD deposition, annealing processes, or insitu deposition and annealing processes. The pass-through chambers 52may additionally perform as degas chambers in addition to performingheating, cooling, and transporting functions.

The second transfer chamber 50 is coupled to reactive preclean chambers42, one or more long throw physical vapor deposition (PVD) chambers 36,and pass-through chambers 52. The second transfer chamber 50configuration allows for substrate precleaning, such as by a plasmaclean method, and PVD deposition at a vacuum pressure of 1×10⁻⁸ Torrprior to transfer to a higher pressure transfer chamber 48. The firsttransfer configuration allows higher pressure processing, such asannealing, compared to PVD processing, to be performed in the transferchamber adjacent loadlocks 46 and prior to substrate removal. The higherpressure first transfer chamber 48 in this embodiment allows for reducedpump down times and reduced equipment costs compared to configuration ofprocessing platform system 35 using a near vacuum pressure, such as at apressure within a range from about 1×10⁻⁵ Torr to about 1×10⁻⁸ Torr, atthe first transfer chamber 48.

FIG. 3 illustrates one embodiment of a long throw physical vapordeposition chamber 36. Example of suitable long throw PVD chambers areALPS® Plus and SIP ENCORE® PVD processing chambers, both commerciallyavailable from Applied Materials, Inc., Santa Clara, Calif.

Generally, the long throw PVD chamber 36 contains a sputtering source,such as a target 142, and a substrate support pedestal 152 for receivinga semiconductor substrate 154 thereon and located within a groundedenclosure wall 150, which may be a chamber wall as shown or a groundedshield.

The chamber 36 includes a target 142 supported on and sealed, as byO-rings (not shown), to a grounded conductive aluminum adapter 144through a dielectric isolator 146. The target 142 comprises the materialto be deposited on the substrate 154 surface during sputtering, and mayinclude cobalt, cobalt silicide, ruthenium, rhodium, titanium, tantalum,tungsten, molybdenum, platinum, nickel, iron, niobium, palladium, alloysthereof, combinations thereof, which are used in forming metal silicidelayers. For example, elemental cobalt, cobalt silicide, nickel cobaltalloys, cobalt tungsten alloys, cobalt nickel tungsten alloys, dopedcobalt and nickel alloys, or nickel iron alloys may be deposited byusing alloy targets or multiple targets in the chamber. The target 142may also include a bonded composite of a metallic surface layer and abacking plate of a more workable metal.

A pedestal 152 supports a substrate 154 to be sputter coated in planaropposition to the principal face of the target 142. The substratesupport pedestal 152 has a planar substrate-receiving surface disposedgenerally parallel to the sputtering surface of the target 142. Thepedestal 152 is vertically movable through a bellows 158 connected to abottom chamber wall 160 to allow the substrate 154 to be transferredonto the pedestal 152 through a load lock valve (not shown) in the lowerportion of the chamber 36 and thereafter raised to a depositionposition. Processing gas is supplied from a gas source 162 through amass flow controller 164 into the lower part of the chamber 36.

A controllable DC power source 148 coupled to the chamber 36 may be usedto apply a negative voltage or bias to the target 142. An RF powersupply 156 may be connected to the pedestal 152 in order to induce anegative DC self-bias on the substrate 154, but in other applicationsthe pedestal 152 is grounded or left electrically floating.

A rotatable magnetron 170 is positioned in back of the target 142 andincludes a plurality of horseshoe magnets 172 supported by a base plate174 connected to a rotation shaft 176 coincident with the central axisof the chamber 36 and the substrate 154. The horseshoe magnets 172 arearranged in closed pattern typically having a kidney shape. The magnets172 produce a magnetic field within the chamber 36, generally paralleland close to the front face of the target 142 to trap electrons andthereby increase the local plasma density, which in turn increases thesputtering rate. The magnets 172 produce an electromagnetic field aroundthe top of the chamber 36, and magnets 172 are rotated to rotate theelectromagnetic field which influences the plasma density of the processto more uniformly sputter the target 142.

The chamber 36 of the invention includes a grounded bottom shield 180having, as is more clearly illustrated in the exploded cross-sectionalview of FIG. 4, an upper flange 182 supported on and electricallyconnected to a ledge 184 of the adapter 144. A dark space shield 186 issupported on the flange 182 of the bottom shield 180, and fasteners (notshown), such as screws recessed in the upper surface of the dark spaceshield 186 fix it and the flange 182 to the adapter ledge 184 havingtapped holes receiving the screws. This metallic threaded connectionallows the two shields 180, 186 to be grounded to the adapter 144. Theadapter 144 in turn is sealed and grounded to an aluminum chambersidewall 150. Both shields 180, 186 are typically formed from hard,non-magnetic stainless steel.

The dark space shield 186 has an upper portion that closely fits anannular side recess of the target 142 with a narrow gap 188 between thedark space shield 186 and the target 142 which is sufficiently narrow toprevent the plasma from penetrating, hence protecting the dielectricisolator 146 from being sputter coated with a metal layer, which wouldelectrically short the target 142. The dark space shield 186 alsoincludes a downwardly projecting tip 190, which prevents the interfacebetween the bottom shield 180 and dark space shield 186 from becomingbonded by sputter deposited metal.

Returning to the overall view of FIG. 3, the bottom shield 180 extendsdownwardly in an upper generally tubular portion 194 of a first diameterand a lower generally tubular portion 196 of a smaller second diameterto extend generally along the walls of the adapter 144 and the chamberwall 150 to below the top surface of the pedestal 152. It also has abowl-shaped bottom including a radially extending bottom portion 198 andan upwardly extending inner portion 100 just outside of the pedestal152. A cover ring 102 rests on the top of the upwardly extending innerportion 100 of the bottom shield 180 when the pedestal 152 is in itslower, loading position but rests on the outer periphery of the pedestal152 when it is in its upper, deposition position to protect the pedestal152 from sputter deposition. An additional deposition ring (not shown)may be used to shield the periphery of the substrate 154 fromdeposition.

The chamber 36 may also be adapted to provide a more directionalsputtering of material onto a substrate. In one aspect, directionalsputtering may be achieved by positioning a collimator 110 between thetarget 142 and the substrate support pedestal 152 to provide a moreuniform and symmetrical flux of deposition material on the substrate154.

A metallic ring collimator 110, such as the Grounded Ring collimator,rests on the ledge portion 106 of the bottom shield 180, therebygrounding the collimator 110. The ring collimator 110 includes an outertubular section and at least one inner concentric tubular sections, forexample, three concentric tubular sections 112, 114, 116 linked by crossstruts 118, 120 as shown in FIG. 5. The outer tubular section 116 restson the ledge portion 106 of the bottom shield 180. The use of the bottomshield 180 to support the collimator 110 simplifies the design andmaintenance of the chamber 36. At least the two inner tubular sections112, 114 are of sufficient height to define high aspect-ratio aperturesthat partially collimate the sputtered particles. Further, the uppersurface of the collimator 110 acts as a ground plane in opposition tothe biased target 142, particularly keeping plasma electrons away fromthe substrate 154.

Another type of collimator usable with the invention is a honeycombcollimator 124, partially illustrated in the plan view of FIG. 6 havinga mesh structure with hexagonal walls 126 separating hexagonal apertures128 in a close-packed arrangement. An advantage of the honeycombcollimator 124 is, if desired, the thickness of the collimator 124 canbe varied from the center to the periphery of the collimator 124,usually in a convex shape, so that the apertures 128 have aspect ratiosthat are likewise varying across the collimator 124. The collimator mayhave one or more convex sides. This allows the sputter flux density tobe tailored across the substrate, permitting increased uniformity ofdeposition. Collimators that may be used in the PVD chamber aredescribed in U.S. Pat. No. 5,650,052, which is hereby incorporated byreference herein to the extent not inconsistent with aspects of theinvention and claims described herein.

One embodiment of a substrate support pedestal 152 is shown in FIG. 7A.The substrate support pedestal 152 is suitable for use in a hightemperature high vacuum annealing process. Generally, the substratesupport pedestal 152 includes a heating portion 210 disposed on a base240 coupled to a shaft 245.

The heating portion 210 generally includes heating elements 250 disposedin a thermally conducting material 220 and a substrate support surface275. The thermally conducting material 220 may be any material that hassufficient thermal conductance at operating temperatures for efficientheat transfer between the heating elements 250 and substrate supportsurface 275. An example of the conducting material is steel. Thesubstrate support surface 275 may include a dielectric material andtypically includes a substantially planar receiving surface for asubstrate 154 disposed thereon.

The heating elements 250 may be resistive heating elements, such aselectrically conducting wires having leads embedded within theconducting material 220, and are provided to complete an electricalcircuit by which electricity is passed through the conducting material220. An example of a heating element 250 includes a discrete heatingcoil disposed in the thermally conducting material 220. Electrical wiresconnect an electrical source (not shown), such as a voltage source, tothe ends of the electrically resistive heating coil to provide energysufficient to heat the coil. The coil may take any shape that covers thearea of the substrate support pedestal 152. More than one coil may beused to provide additional heating capability, if needed.

Fluid channels 290 may be coupled to a surface 226 of the heatingportion 210 and may provide for either heating or cooling of thesubstrate support pedestal 152. The fluid channels 290 may include aconcentric ring or series of rings (not shown), or other desiredconfiguration, having fluid inlets and outlets for circulating a liquidfrom a remotely located fluid source 294. The fluid channels 290 areconnected to the fluid source 294 by fluid passage 292 formed in theshaft 245 of substrate support pedestal 152. Embodiments of thesubstrate support pedestal 152 including both heating elements 250coupled to an electrical source 296 and fluid channels 290 cooled by athermal medium passing through fluid passage 292 connected to the fluidsource 294, i.e., a liquid heat exchanger, generally achieve temperaturecontrol of substrate support surface 275.

Temperature sensors 260, such as a thermocouple, may be attached to orembedded in the substrate support pedestal 152, such as adjacent theheating portion 210, to monitor temperature in a conventional manner.For example, measured temperature may be used in a feedback loop tocontrol electric current applied to the heating elements 250 from theelectrical source 296, such that substrate temperature can be maintainedor controlled at a desired temperature or within a desired temperaturerange. A control unit (not shown) may be used to receive a signal fromtemperature sensor 260 and control the heat electrical source 296 or afluid source 294 in response.

The electrical source 296 and the fluid source 294 of the heating andcooling components are generally located external of the chamber 36. Theutility passages, including the fluid passage 292, are disposed axiallyalong the base 240 and shaft 245 of the substrate support pedestal 152.A protective, flexible sheath 295 is disposed around the shaft 245 andextends from the substrate support pedestal 152 to the chamber wall (notshown) to prevent contamination between the substrate support pedestal152 and the inside of the chamber 36.

The substrate support pedestal 152 may further contain gas channels (notshown) fluidly connecting with substrate support surface 275 of theheating portion 210 to a source of backside gas (not shown). The gaschannels define a backside gas passage of a heat transfer gas or maskinggas between the heating portion 210 and the substrate 154.

FIG. 7B illustrates another embodiment of the substrate support pedestal152 having an electrostatic chuck mounted to or forming the heatingportion 210 of the substrate support pedestal 152. The heating portion210 includes an electrode 230 and substrate support surface 275 coatedwith a dielectric material 235. Electrically conducting wires (notshown) couple the electrodes 230 to a voltage source (not shown). Asubstrate 154 may be placed in contact with the dielectric material 235,and a direct current voltage is placed on the electrode 230 to createthe electrostatic attractive force to grip the substrate.

Generally, the electrodes 230 are disposed in the thermally conductingmaterial 220 in a spaced relationship with the heating elements 250disposed therein. The heating elements 250 are generally disposed in avertically spaced and parallel manner from the electrodes 230 in thethermally conducting material 220. Typically, the electrodes aredisposed between the heating elements 250 and substrate support surface275 though other configurations may be used.

The embodiments of the substrate support pedestals 152 described abovemay be used to support a substrate in a high vacuum annealing chamber.The high vacuum annealing chamber may include substrate supportpedestals 152 disposed in a PVD chamber, such as the long throw chamber36 described herein, with a blank target disposed therein or without atarget and without bias coupled to either the target or substratesupport pedestal.

Embodiments of the substrate support pedestal 152 are described aboveand are provided for illustrative purposes and should not be construedor interpreted as limiting the scope of the invention. For example,suitable electrostatic chucks that may be used for the support pedestalinclude MCAT™ Electrostatic E-chuck or Pyrolytic Boron NitrideElectrostatic E-Chuck, both available from Applied Materials, Inc., ofSanta Clara, Calif.

While the embodiments of substrate support pedestal 152 described hereinmay be used to anneal the substrate, commercially available annealingchambers, such as rapid thermal anneal (RTA) chambers may also be usedto anneal the substrate to form the silicide films. The inventioncontemplates utilizing a variety of thermal annealing chamber designs,including hot plate designs and heated lamp designs, to enhance theelectroplating results. One particular thermal annealing chamber usefulfor the invention is the WXZ™ chamber available from Applied Materials,Inc., located in Santa Clara, Calif. One particular hot plate thermalannealing chamber useful for the invention is the RTP XEplus CENTURA®thermal processing chamber available from Applied Materials, Inc.,located in Santa Clara, Calif. One particular lamp annealing chamber isthe RADIANCE® thermal processing chamber available from AppliedMaterials, Inc., located in Santa Clara, Calif.

Referring to FIGS. 1 and 2, the processing chambers 36, 38, 40, 41, 42and 43, are each controlled by a microprocessor controller 54. Themicroprocessor controller 54 may be one of any form of general purposecomputer processor (CPU) that can be used in an industrial setting forcontrolling process chambers as well as sub-processors. The computer mayuse any suitable memory, such as random access memory, read only memory,floppy disk drive, hard drive, or any other form of digital storage,local or remote. Various support circuits may be coupled to the CPU forsupporting the processor in a conventional manner. Software routines asrequired may be stored in the memory or executed by a second CPU that isremotely located.

The process sequence routines are executed after the substrate 154 ispositioned on the pedestal 152. The software routines, when executed,transform the general purpose computer into a specific process computerthat controls the chamber operation so that a chamber process isperformed. Alternatively, the software routines may be performed inhardware, as an application specific integrated circuit or other type ofhardware implementation, or a combination of software and hardware.

In operation, the substrate 154 is positioned on the substrate supportpedestal 152 and plasma is generated in the chamber 36. A long throwdistance of at least about 90 mm separates the target 142 and thesubstrate 154. The substrate support pedestal 152 and the target 142 maybe separated by a distance within a range from about 100 mm to about 300mm for a 200 mm substrate. The substrate support pedestal 152 and thetarget 142 may be separated by a distance within a range from about 150mm to about 400 mm for a 300 mm substrate. Any separation between thesubstrate 154 and target 142 that is greater than 50% of the substratediameter is considered a long throw processing chamber.

The sputtering process is performed by applying a negative voltage,typically between about 0 V and about 2,400 V, to the target 142 toexcite the gas into a plasma state. The direct current (DC) power supply148 or another power supply may be used to apply a negative bias, forexample, between about 0 V and about 700 V, to the substrate supportpedestal 152. Ions from the plasma bombard the target 142 to sputteratoms and larger particles onto the substrate 154 disposed below. Whilethe power supplied is expressed in voltage, power may also be expressedas a unit of power (e.g., kilowatts) or a unit of power density (e.g.,w/cm²). The amount of power supplied to the chamber 36 may be varieddepending upon the amount of sputtering and the size of the substrate154 being processed.

Processing gas used for the sputtering process is introduced into theprocessing chamber 36 via the mass flow controller 164. The processinggas includes non-reactive or inert species such as argon, xenon, helium,or combinations thereof. A vacuum pumping system 166 connected through apumping port 168 in the lower chamber is used to maintain the chamber 36at a base pressure of less than about 1×10⁻⁶ Torr, such as about 1×10⁻⁸Torr, but the processing pressure within the chamber 36 is typicallymaintained at between 0.2 milliTorr and 2 milliTorr, preferably lessthan 1 milliTorr, for cobalt sputtering.

In operation, a substrate 154 is disposed on the substrate supportpedestal 152, and the substrate 154 is heated, with or without thepresence of a backside gas source 272, by the heating elements 250 tothe desired processing temperature, processed for sufficient time toanneal the substrate 154 for the desired anneal results, and thenremoved from the chamber 36. The heating elements 250 of the substratesupport pedestal 152 may heat the substrate 154 from room temperature,i.e., about 20° C. to about 900° C. and the fluid channels 290 may coolthe substrate 154 to a temperature of about 0° C. The combination ofheating elements 250 and the fluid channels 290 are generally used tocontrol the temperature of a substrate 154 between about 10° C. andabout 900° C., subject to properties of materials used in substratesupport pedestal 152 and the process parameters used for processing asubstrate in the chamber 36.

Metal and Metal Silicide Barrier Deposition Processes

Embodiments of the processes described herein relate to depositing metaland cobalt silicide barrier layers for feature definitions. In oneembodiment, a metallic cobalt layer is deposited on a silicon-containingmaterial and annealed to form a cobalt silicide layer. A second metalliccobalt layer is deposited onto the cobalt silicide layer. At least onemetallic contact material is subsequently deposited to fill the feature.The annealing process for forming the metal silicide layer may beperformed in multiple annealing steps. The deposition of the first metallayer, the second metal layer, and any required annealing steps arepreferably performed without breaking vacuum in one vacuum processingsystem.

In one embodiment, a cobalt silicide layer is deposited on asilicon-containing material. A metallic cobalt layer is deposited on thecobalt silicide layer. Subsequently, at least one metallic contactmaterial may be deposited to fill the feature. An annealing process maybe performed prior to, during, or after each of the deposition processand are preferably performed without breaking vacuum in one vacuumprocessing system.

The first annealing step may be performed in the same chamber as thedeposition of the first metal, an annealing chamber, such as a vacuumannealing chamber, or during deposition of subsequent materials, such asduring a CVD of the second metal. The second annealing step may beperformed before or after the deposition of the second metal. The secondannealing process generally has a higher annealing temperature than thefirst annealing process.

Preferably, the metal silicide layer may be formed in situ, such as in adeposition chamber or in a processing system without breaking vacuum,prior to or concurrently with depositing a metal layer by a CVDtechnique. In situ is broadly defined herein as performing two or moreprocesses in the same chamber or in the same processing system withoutbreaking vacuum (e.g., opening the chamber) or transfer to a separateapparatus or system.

For example, in situ annealing may be performed in the same processingchamber as the metal deposition and in situ deposition may performed ina processing chamber adjacent to the deposition chamber, both of whichare coupled to a transfer chamber, and the vacuum on the transferchamber is not broken during processing.

In a further example, in situ processing may be performed on the sameprocessing system at separate processing pressures, such as processing asubstrate in processing chambers and annealing chambers disposed on thefirst and second transfer chambers 48, 50, respectfully, in processingplatform system 35 without breaking the vacuum on processing platformsystem 35 or transfer of the substrate to another processing system.

While the following material describes the formation of a metal silicidelayer from a cobalt or nickel layer film, the invention contemplates theuse of other materials, including titanium, tantalum, tungsten,molybdenum, platinum, iron, niobium, palladium, and combinationsthereof, and other alloys including nickel cobalt alloys, cobalttungsten alloys, cobalt nickel tungsten alloys, doped cobalt and nickelalloys, or nickel iron alloys, to form the metal silicide material asdescribed herein.

Reactive Preclean

Prior to metal deposition on a substrate, the surface of the substrate154 may be cleaned to remove contaminants, such as oxides formed onexposed. The cleaning process may be performed by a wet etch process,such as exposure to a hydrofluoric acid solution, or by a plasmacleaning process, such as exposure to a plasma of an inert gas, areducing gas, such as hydrogen or ammonia, or combinations thereof. Thecleaning process may also be performed between processing steps tominimize contamination of the substrate surface during processing.

The plasma clean process may be performed in the PreClean II processingchamber and the RPC+ processing chamber described herein, of which bothare commercially available form Applied Materials, Inc., of Santa ClaraCalif. In one aspect, the reactive preclean process forms radicals froma plasma of one or more gases such as argon, helium, hydrogen, nitrogen,fluorine-containing compounds, and combinations thereof. For example, apreclean gas may include a mixture of carbon tetrafluoride (CF₄) andoxygen (O₂), or a mixture of helium and nitrogen trifluoride (NF₃). In apreferred example, the preclean gas is an argon plasma. In anotherexample, the preclean gas contains a hydrogen plasma. In anotherexample, the preclean gas contains a mixture of helium and nitrogentrifluoride.

The plasma is typically generated by applying a power between about 500watts and about 2,000 watts RF at a frequency between about 200 kHz andabout 114 MHz. The flow of helium may be within a range from about 100sccm to about 500 sccm and the flow of nitrogen trifluoride typicallymay be within a range from about 100 sccm to about 500 sccm for 200 mmsubstrates. The plasma treatment lasts between about 10 seconds andabout 150 seconds. Preferably, the plasma is generated in one or moretreatment cycles and purged between cycles. For example, four treatmentcycles lasting about 35 seconds each is effective.

In another aspect, the substrate 154 may be precleaned using an argonplasma first and then a hydrogen plasma. A first preclean gas comprisinggreater than about 50% argon by number of atoms may be introduced at apressure of about 0.8 milliTorr. A plasma of the argon gas is struck tosubject the substrate 154 to an argon sputter cleaning environment. Theargon plasma is preferably generated by applying between about 50 wattsand about 500 watts of RF power. The argon plasma is maintained for atime period within a range from about 10 seconds to about 300 seconds toprovide sufficient cleaning time for the deposits that are not readilyremoved by a reactive hydrogen plasma.

Following the argon plasma, the chamber pressure may be increased toabout 140 milliTorr, and a second preclean gas consisting essentially ofhydrogen and helium is introduced into the processing region.Preferably, the processing gas comprises about 5% hydrogen and about 95%helium. The hydrogen plasma is generated by applying between about 50watts and about 500 watts of power. The hydrogen plasma is maintainedfor about 10 seconds to about 300 seconds.

Metal Deposition

A first metal layer may be deposited on a substrate 154 disposed inchamber 36 as a barrier layer for a second metal layer “plug” or may bedeposited and annealed on the substrate pedestal 152 to form the metalsilicide layer without breaking vacuum. The substrate 154 includesdielectric materials, such as silicon or silicon oxide materials,disposed thereon and is generally patterned to define features intowhich metal films may be deposited or metal silicide films will beformed. The first metal layer may be deposited by a physical vapordeposition technique, a CVD technique, or an atomic layer depositiontechnique.

In a PVD process, the metal is deposited using the PVD chamber 36described above. The target 142 of material, such as cobalt, to bedeposited is disposed in the upper portion of the chamber 36. Asubstrate 154 is provided to the chamber 36 and disposed on thesubstrate support pedestal 152. A processing gas is introduced into thechamber 36 at a flow rate of between about 5 sccm and about 30 sccm. Thechamber pressure is maintained below about 5 milliTorr to promotedeposition of conformal PVD metal layers. Preferably, a chamber pressurebetween about 0.2 milliTorr and about 2 milliTorr may be used duringdeposition. More preferably, a chamber pressure between about 0.2milliTorr and about 1.0 milliTorr has been observed to be sufficient forsputtering cobalt onto a substrate.

Plasma is generated by applying a negative voltage to the target 142between about 0 volts (V) and about −2,400 V. For example, negativevoltage is applied to the target 142 at between about 0 V and about−1,000 V to sputter material on a 200 mm substrate. A negative voltagebetween about 0 V and about −700 V may be applied to the substratesupport pedestal 152 to improve directionality of the sputtered materialto the substrate surface. The substrate 154 is maintained at atemperature within a range from about 10° C. to about 600° C. during thedeposition process.

An example of a deposition process includes introducing an inert gas,such as argon, into the chamber 36 at a flow rate between about 5 sccmand about 30 sccm, maintaining a chamber pressure between about 0.2milliTorr and about 1.0 milliTorr, applying a negative bias of betweenabout 0 volts and about 1,000 volts to the target 142 to excite the gasinto a plasma state, maintaining the substrate 154 at a temperaturewithin a range from about 10° C. to about 600° C., preferably about 50°C. and about 300° C., and more preferably, between about 50° C. andabout 100° C. during the sputtering process, and spacing the target 142between about 100 mm and about 300 mm from the substrate surface for a200 mm substrate. Cobalt may be deposited on the silicon material at arate between about 300 Å/min and about 2000 Å/min using this process. Acollimator 110 or 124 may be used with the process described herein withminimal detrimental affect on deposition rate.

While not shown, the barrier material, such as cobalt silicide, cobaltor nickel described above, may be deposited by another method using theapparatus shown in FIGS. 1 and 2. The cobalt material may be depositedby a CVD technique, an ALD technique, an ionized magnetic plasma PVD(IMP-PVD) technique, a self-ionized plasma PVD (SIP-PVD) technique, anelectroless deposition process, or combinations thereof. For example,the cobalt material may be deposited by CVD in a CVD chamber, such aschamber 38 of processing platform system 35 as shown in FIG. 1, or byALD in an ALD chamber or CVD chamber disposed at position 38, as shownin FIG. 1. The substrates may be transferred between various chamberswithin processing platform system 35 without breaking a vacuum orexposing the substrates to other external environmental conditions.

Alternatively, prior to second metal deposition, such as tungsten, alayer of a barrier material, such as titanium or titanium nitride, maybe deposited on the first metal layer. The layer of barrier materialimproves resistance to interlayer diffusion of the second metal layerinto the underlying substrate or silicon material. Additionally, thelayer of barrier material may improve interlayer adhesion between thefirst and second metal layers. Suitable barrier layer materials includetitanium, titanium nitride, tantalum, tantalum nitride, tungsten,tungsten nitride, titanium-tungsten alloy, derivatives thereof, andcombinations thereof. The layer of barrier materials may be deposited bya CVD technique, an ALD technique, an IMP-PVD technique, a SIP-PVDtechnique, or combinations thereof.

Tungsten Deposition

In one aspect, the substrate is then transferred to a CVD chamber forthe deposition of a second metal layer, such as tungsten, on the firstmetal layer, such as cobalt or nickel. Tungsten may be deposited by CVDtechnique. Tungsten may be deposited at a sufficient temperature, suchas between about 300° C. and about 500° C., to initiate the formation ofa metal silicide, such as cobalt silicide. The metal silicide may beformed from part or all of the first metal layer.

An annealing step may be performed in the processing chamber, such asthe WXZ™, prior to material deposition. Such an annealing step isperformed at a temperature within a range from about 300° C. to about900° C., such as from about 300° C. to about 400° C. A thin layer ofsilicon, or “silicon soak” may be deposited on the barrier layer priorto deposition of any tungsten material. The silicon deposition may beperformed in situ with the same chamber as the tungsten materialdeposition. Additionally, a tungsten nucleation step may be performedprior to a main tungsten deposition. The tungsten nucleation step may beperformed in situ by an ALD technique or CVD process in the same CVDchamber as the main tungsten deposition or subsequent tungstendeposition.

An example of a tungsten CVD process includes depositing a siliconlayer, also known as a silicon soak layer, a tungsten nucleation layerdeposition, and a main, or bulk, tungsten deposition. The silicon layeris deposited by introducing a silane gas (e.g., SiH₄, Si₂H₆, orderivatives thereof) into the chamber 36 at a flow rate between about 50sccm and about 100 sccm, a reactive gas, such as hydrogen (H₂), into thechamber at a flow rate between about 500 sccm and about 5,000 sccm, andan inert gas, such as argon or nitrogen, into the chamber 36 at a flowrate between about 500 sccm and about 5,000 sccm, maintaining thechamber pressure between about 100 milliTorr and about 300 Torr, andmaintaining the substrate temperature within a range from about 300° C.to about 500° C. The process may be performed for a time period within arange from about 5 seconds to about 30 seconds. The silicon layer isusually deposited at a thickness of about 1,000 Å or less.

The tungsten nucleation layer is deposited by a process includingintroducing a tungsten precursor gas, such as tungsten hexafluoride(WF₆) or derivative thereof, into the chamber 36 at a flow rate betweenabout 5 sccm and about 60 sccm, a silane gas (e.g., SiH₄, Si₂H₆, orderivatives thereof) into the chamber 36 at a flow rate between about 5sccm and about 60 sccm, a reactive gas, such as hydrogen (H₂), into thechamber 36 at a flow rate between about 500 sccm and about 5,000 sccm,and an inert gas, such as argon or nitrogen, into the chamber 36 at aflow rate between about 500 sccm and about 5,000 sccm, and maintaining achamber pressure between about 100 milliTorr and about 300 Torr, andmaintaining the substrate temperature within a range from about 300° C.to about 500° C. The process may be performed for a time period within arange from about 5 seconds to about 30 seconds. The nucleation layer isusually deposited at a thickness of about 1,000 Å or less.

The tungsten layer is then deposited on the tungsten nucleation layer bya process including introducing a tungsten precursor gas, such astungsten hexafluoride or derivative thereof, into the chamber 36 at aflow rate between about 25 sccm and about 250 sccm, a reactive gas, suchas hydrogen (H₂), into the chamber 36 at a flow rate between about 500sccm and about 5,000 sccm, and an inert gas, such as argon or nitrogen,into the chamber 36 at a flow rate between about 500 sccm and about5,000 sccm, and maintaining a chamber pressure between about 100milliTorr and about 300 Torr, and maintaining the substrate temperaturewithin a range from about 300° C. to about 900° C. The process may beperformed for a time period within a range from about 5 seconds to about300 seconds or until a desired thickness is reached. The deposition ratefor tungsten is between about 1,000 Å/min and about 3,000 Å/min.

The substrate temperature during the main tungsten deposition process ismaintained at sufficient temperature to initiate the formation of ametal silicide layer from silicon material on the substrate 154 and thefirst metal layer disposed thereon. For example, a substrate temperaturewithin a range from about 300° C. to about 900° C., such as betweenabout 300° C. and about 400° C., may be maintained to form the silicidelayer with diffusion barrier properties simultaneously with tungstendeposition.

An example of the tungsten deposition process includes a silicon soaklayer formed by introducing a silane gas at a flow rate of about 75sccm, introducing hydrogen (H₂) at a flow rate of about 1,000 sccm,introducing argon or nitrogen at a flow rate of about 1,500 sccm,maintaining the chamber pressure at about 90 Torr, and maintaining thesubstrate temperature at about 425° C. The process may be performed fora time period within a range from about 10 seconds to about 20 seconds.The nucleation layer is deposited by introducing tungsten hexafluorideat a flow rate of about 20 sccm, silane gas at a flow of about 10 sccm,hydrogen gas at a flow rate of about 3,000 sccm, and argon at a flowrate of about 3,000 sccm, and maintaining a chamber pressure at about 30Torr, and maintaining the substrate temperature at about 425° C. Thisprocess may be performed for about 15 seconds. The tungsten layer isdeposited by introducing tungsten hexafluoride at a flow rate of about250 sccm, hydrogen gas at a flow rate of about 1,000 sccm, and argon ata flow rate of about 3,000 sccm, and maintaining a chamber pressure atabout 300 Torr, and maintaining the substrate temperature at about 425°C. This process may be performed for a time period within a range fromabout 40 seconds to about 45 seconds.

General In-Situ Annealing Process

Alternatively, the first metal layer may be annealed in situ by one ormore annealing steps at an annealing temperature within a range fromabout 300° C. to about 900° C. to form the metal silicide layer prior tothe deposition of the second metal layer. The one or more annealingsteps may be performed for a time period within a range from about 10seconds to about 600 seconds. A selective etch of the first metal layerand metal silicide layer to remove unreacted first metal material may beperformed between two or more annealing steps. Deposition of materials,such as a layer of barrier material or the second metal layer, may beperformed between two or more annealing steps.

In one example of the annealing process, the substrate 154 may beannealed under an inert gas environment in the deposition chamber byfirst introducing an inert gas into the chamber 36 at a flow ratebetween about 0 sccm (i.e., no backside gas) and about 15 sccm,maintaining a chamber pressure of about 2 milliTorr or less, and heatingthe substrate 154 to a temperature within a range from about 300° C. toabout 900° C. for a time period within a range from about 5 seconds toabout 600 seconds to form the metal silicide layer.

Low Temperature Deposition and Two-Step In-Situ Annealing Process in TwoChambers

In another embodiment, the metal layer may be physical vapor depositedon a silicon substrate in chamber 36, annealed at a first temperaturefor a first period of time, transferred to a second chamber, for examplechamber 41, in processing platform system 35, and annealed at a secondtemperature for a second period of time to form the metal silicide layerwithout breaking vacuum.

The physical vapor deposition of the metal is performed as describedabove at a temperature of about 200° C. or less, preferably betweenabout 0° C. and about 100° C. The first step of the two step in situannealing process described above may be performed under an inert gasenvironment in the deposition chamber by first introducing an inert gasinto the chamber at a flow rate between about 0 sccm and about 15 sccmor less, maintaining a chamber pressure of about 2 milliTorr or less,heating the substrate 154 to a temperature within a range from about400° C. to about 600° C. for a time period within a range from about 5seconds to about 300 seconds. Preferably, the substrate 154 is annealedin the deposition chamber at about 500° C. for a time period within arange from about 60 seconds to about 120 seconds. Performing the firstannealing the substrate in the same chamber as the deposition process ispreferred over other annealing processes described herein.

The substrate 154 may be removed from the deposition chamber andtransferred to a vacuum annealing chamber disposed on the same transferchamber, such as transfer chamber 48 described above in FIG. 1. The highvacuum annealing chamber may include a PVD chamber having a blank targetand substrate support pedestal 152 described above or a commercial highvacuum anneal pedestal, such as the High Temperature High Uniformity(HTHU) substrate support commercially available from Applied MaterialsInc., of Santa Clara Calif.

The second annealing step may then be performed by maintaining a chamberpressure of about 2 milliTorr or less and heating the substrate 154 to atemperature within a range from about 600° C. to about 900° C. for aperiod of time between about 5 seconds and about 300 seconds to form themetal silicide layer. Preferably, the substrate is annealed in theannealing chamber at 800° C. for a time period within a range from about60 seconds to about 120 seconds.

Low Temperature Deposition and Two-Step Annealing Process in TwoChambers

In an alternative embodiment of the two chamber deposition and annealingprocess, the metal layer is deposited according to the process describedherein at about 200° C. or less, preferably between about 0° C. andabout 100° C., in the deposition chamber. Substrate 154 may be annealedin the deposition chamber according to the annealing process describedabove. Subsequently, substrate 154 may be transferred to an RTA chamberdisposed on transfer chamber 50 in FIG. 1 for a second annealingprocess.

Annealing in an RTA chamber may be performed by introducing a processgas including nitrogen (N₂), argon, helium, and combinations thereof,with less than about 4% hydrogen (H₂), at a process gas flow rategreater than 20 liters/min to control the oxygen content to less than100 ppm, maintaining a chamber pressure of about ambient, and heatingthe substrate 154 to a temperature within a range from about 600° C. toabout 900° C. for a time period within a range from about 5 seconds toabout 300 seconds to form the metal silicide layer. Preferably, thesubstrate 154 is annealed in the RTA annealing chamber at 800° C. forabout 30 seconds.

Low Temperature Deposition and Two-Step Annealing Process in ThreeChambers

In another embodiment, the metal layer may be deposited on a siliconsubstrate in chamber 36, transferred to a first annealing chamber, suchas a vacuum annealing chamber disposed on the same transfer chamber 48on processing platform system 35, annealed at a first temperature for afirst period of time, transferred to a second annealing chamber, forexample chamber 41, in processing platform system 35, and annealed at asecond temperature for a second period of time to form the metalsilicide layer without breaking vacuum.

The metal deposition is performed in the deposition chamber according tothe process described above at a substrate temperature of about 200° C.or less, preferably between about 0° C. and about 100° C. The first stepof this embodiment of the annealing process may be performed in situ ina first high vacuum annealing chamber disposed on a processing system byintroducing an inert gas into the annealing chamber at a flow rate of 0sccm and about 15 sccm, maintaining a chamber pressure about 2 milliTorror less, heating the substrate 154 to a temperature within a range fromabout 400° C. to about 600° C. for a time period within a range fromabout 5 seconds to about 300 seconds. Preferably, the substrate 154 isannealed in the deposition chamber at about 500° C. for a time periodwithin a range from about 60 seconds to about 120 seconds. The firstannealing step is believed to form an oxygen resistant film such asCoSi.

The substrate 154 may be annealed in situ by transfer to a second highvacuum annealing chamber in processing platform system 35. The secondannealing step may then be performed by maintaining a chamber pressureof about 2 milliTorr or less and heating the substrate to a temperaturewithin a range from about 600° C. to about 900° C. for a period of timebetween about 5 seconds and about 300 seconds to form the metal silicidelayer. Preferably, the substrate 154 is annealed in the annealingchamber at 800° C. for a time period within a range from about 60seconds to about 120 seconds.

Alternatively, the substrate 154 may be transferred to a secondannealing chamber located outside the transfer chamber 48, 50 orprocessing platform system 35, such as an atmospheric pressure RTAchamber. Annealing in an atmospheric pressure RTA chamber may beperformed by introducing a process gas including nitrogen (N₂), argon,helium, and combinations thereof, with less than about 4% hydrogen (H₂),at a process gas flow rate greater than 20 liters/min to control theoxygen content to less than 100 ppm, maintaining a chamber pressure ofabout ambient, and heating the substrate 154 to a temperature within arange from about 400° C. to about 900° C. for a time period within arange from about 5 seconds to about 300 seconds to form the metalsilicide layer. Preferably, the substrate 154 is annealed in the RTAchamber at 800° C. for about 30 seconds.

High Temperature Deposition and Annealing Process

The metal may be deposited at a high deposition temperature. An exampleof a deposition process includes introducing an inert gas, such asargon, into the chamber 36 at a flow rate between about 5 sccm and about30 sccm, maintaining a chamber pressure between about 0.2 milliTorr andabout 1.0 milliTorr, applying a negative bias of between about 0 voltsand about 1,000 volts to the target 142 to excite the gas into a plasmastate, maintaining the substrate 154 at an annealing temperature, i.e.,between about 400° C. and about 600° C., by applying a backside gas, andspacing the target 142 between about 100 mm and about 300 mm from thesubstrate surface for a 200 mm substrate. The temperature may bemaintained at about 200° C. by heating the substrate in the absence of abackside gas. Cobalt may be deposited on the silicon material at a ratebetween about 100 Å/min and about 2,000 Å/min using this process.

The annealing process can then be performed in the deposition chamber byending the plasma and heating of the substrate 154 to a temperaturewithin a range from about 400° C. to about 600° C. at the same heatinglevels used for the deposition process. The annealing process isperformed at a temperature within a range from about 400° C. to about600° C. for a time period within a range from about 5 seconds to about300 seconds. Preferably, the substrate 154 is annealed in the depositionchamber at about 500° C. for a time period within a range from about 60seconds to about 120 seconds.

The second annealing step may then be formed in an annealing chamberwithout breaking vacuum or in an annealing chamber located on a separatetransfer chamber or processing system. The second annealing stepincludes heating the substrate 154 to a temperature within a range fromabout 600° C. to about 900° C. for a period of time between about 5seconds and about 300 seconds to form the metal silicide layer.Preferably, the substrate 154 is annealed at 800° C. for a time periodwithin a range from about 60 seconds to about 120 seconds.

Interlayer Deposition and Annealing process

In one aspect of the invention, the two-step annealing process describedherein may be separated by one or more processing steps, such asdeposition processes. For example, a first metal layer, such as a cobaltor nickel layer, may be deposited in a first chamber, in situ annealedin the first transfer chamber or transferred to a second chamber forsubsequent deposition and annealed therein. A second metal layer, suchas tungsten is then deposited on the annealed substrate 154, and thesubstrate 154 is exposed to a second anneal in the second chamber ortransferred to a third chamber for the completion of the annealingprocess.

In another example, a first metal layer, such as a cobalt or nickellayer may be deposited in a first chamber, in situ annealed inprocessing platform system 35, transferred to a second depositionchamber for deposition of a barrier material thereon, such as titaniumnitride, transferred to a third deposition chamber for deposition of asecond metal, and then further annealed in the third chamber ortransferred to a fourth chamber for the completion of the annealingprocess. The substrate may be transferred between any of the fourchambers without a vacuum break. Alternatively, the in situ anneal ofthe first metal layer may be performed after the deposition of thebarrier material and prior to the deposition of the second metal layer,such as tungsten.

Examples of Metal and Metal Silicide Deposition

An example of a deposition process of a metal silicide layer as abarrier layer for a tungsten plug in a feature definition is as followsand shown in FIGS. 8A-8C. A substrate 300 having a silicon-containingmaterial 310 formed thereon with feature definitions 320 formed thereinis provided to processing platform system 35. The silicon-containingmaterial 310 may be a dielectric material including silicon, siliconoxide, a doped silicon or silicon oxide layer, or othersilicon-containing dielectric material used in substrate processing,which may be deposited by an atomic layer epitaxy (ALE) process or a CVDprocess. Embodiments of the invention also contemplates that layer 310may include semi-conductive silicon-containing materials includingpolysilicon, doped polysilicon, or combinations thereof, deposited bymethods known or unknown in the art.

Feature definitions 320 are formed in the silicon-containing material310 by conventional method known in the art. For example, the featuredefinitions 320 may be formed by depositing and patterning a photoresistmaterial to define the feature openings, a silicon etch process is thenused to define the feature definitions 320, and any remainingphotoresist material is removed, such as by an oxygen stripping method.The feature definitions 320 may then be treated with a plasma cleanprocess to remove any contaminants, such as oxide formed on thesilicon-containing material, prior to deposition of subsequent materialsas described herein. A layer of cobalt silicide or metallic cobalt isdeposited as a barrier layer 330 by an ALD process, a CVD process, or aPVD process described herein over the bottom and sidewalls of thefeature definitions 320 as shown in FIG. 8A.

The cobalt barrier layer 330 may be annealed to form cobalt silicide atthe interface 325 of the cobalt layer and the silicon containingmaterial 310. Depending on the annealing process used, substantially allor only a portion of the cobalt barrier layer 330 may be converted tocobalt silicide. When the cobalt material is not substantially convertedto the cobalt silicide material, a surface 335 of unreacted cobalt isformed which is exposed to subsequently deposited materials as shown inFIG. 8B. This cobalt surface 335 may be maintained to further act asadditional barrier layer material for subsequent metal deposition, suchas tungsten, or may be removed from the substrate 300 surface by an etchprocess.

A layer of tungsten 350 is deposited to fill the feature definition 320as shown in FIG. 8C. The tungsten deposition may be at a high enoughtemperature to completely convert any unreacted cobalt material tocobalt silicide, in effect annealing the cobalt material, whiledepositing to fill the feature definition 320. Alternatively, a secondannealing step is performed to substantially convert the cobalt barrierlayer 330 to a cobalt silicide layer 340.

Such a cobalt silicide barrier and tungsten fill of the featuredefinition 320 may be processed in processing platform system 35 asfollows. Referring to FIG. 2, the substrate 300 is introduced into thefirst transfer chamber 48 of processing platform system 35 via theloadlock 46. The first transfer chamber 48 is operating at about 400milliTorr. Transfer robot 49 retrieves the substrate 300 from theloadlock 46 and transfers it to pass-through chamber 52. Transfer robot51 in the second transfer chamber 50 retrieves the substrate 300 fromthe pass-through chamber 52 and positions the substrate 300 in PVDchamber 38 for cobalt deposition. The second transfer chamber 50 isoperated at about 1×10⁻⁸ Torr. Alternatively, the transfer robot 51positions the substrate 300 in one of the preclean chambers prior tocobalt deposition in the PVD chamber 38. Following PVD deposition, thesubstrate 300 is transferred back to the first transfer chamber 48 anddisposed in a WXZ™ CVD chamber 38 for CVD tungsten deposition. Thesubstrate may then be annealed as necessary.

Alternatively, following PVD deposition, the substrate 300 is disposedin chamber 41, which is a WXZ™ chamber capable of in situ annealing,where the cobalt material is first annealed to form a silicide materialor to improve barrier properties prior to CVD deposition. A layer oftungsten may then be deposited in the WXZ™ chamber following the annealstep. However, the substrate 300 may be transferred after the firstanneal in the WXZ™ chamber to a plasma etch chamber, such as a DPS®chamber, for etching to remove cobalt and then annealed a second time inthe WXZ™ chamber or another annealing chamber prior to tungstendeposition. Following deposition, and annealing if necessary, thesubstrate 300 is transferred to the loadlock chamber 46 via the transferrobot 49. The substrate 300 may then be transferred to a separateapparatus, such as a chemical-mechanical polishing apparatus, forfurther processing.

Another metal silicide application includes the formation of a MOSdevice shown in FIG. 9. The metal silicide includes silicides of cobalt,titanium, tantalum, tungsten, molybdenum, platinum, nickel, iron,niobium, palladium, or combinations thereof, for use in an MOS device.

In the illustrated MOS structure, N+ source and drain regions 402 and404 are formed in a P type silicon substrate 400 adjacent field oxideportions 406. A gate oxide layer 408 and a polysilicon gate electrode410 are formed over silicon substrate 400 in between source and drainregions 402 and 404 with oxide spacers 412 formed on the sidewalls ofpolysilicon gate electrode 410.

A cobalt layer is deposited over the MOS structure, and in particularover the exposed silicon surfaces of source and drain regions 402 and404 and the exposed top surface of polysilicon gate electrode 410 by theprocess described herein. The cobalt material is deposited to athickness of at about 1,000 Å or less to provide a sufficient amount ofcobalt for the subsequent reaction with the underlying silicon at drainregions 402 and 404. Cobalt may be deposited to a thickness within arange from about 50 Å to about 500 Å on the silicon material. In oneaspect, the cobalt layer is then annealed in situ as described herein toform cobalt silicide.

While not shown, a barrier or liner layer of a material, such astitanium nitride, may be deposited on the cobalt material to furtherenhance the barrier properties of the cobalt layer. The deposition ofthe titanium nitride layer may replace the step of removing unreactedcobalt as described above. However, the unreacted cobalt and titaniummay be removed by the etch process after annealing of the substratesurface according to the annealing processes described herein.

The substrate 400 may then be annealed again according to one of thetwo-step annealing processes described herein. Dielectric materials 422may be deposited over the formed structure and etched to provide contactdefinitions 420 in the device. The contact definitions 420 may then befilled with a contact material, such as tungsten, aluminum, copper, oralloy thereof, by an ALD process, a CVD process, or combinationsthereof, such as described herein.

In one aspect, any unreacted cobalt from the annealing processes may beremoved from the substrate surface, typically by a wet etch process orplasma etch process, and the cobalt silicide remains as cobalt silicide(CoSi₂) portions 414, 416, and 418 of uniform thickness respectivelyformed over polysilicon gate electrode 410 and over source and drainregions 402 and 404 in silicon substrate 400. Unreacted cobalt may beremoved by a plasma process in a DPS® chamber located on the same vacuumprocessing system, or may be transferred to another processing systemfor processing. Wet etch process are typically performed in a secondprocessing system.

Cobalt Silicide and Metallic Cobalt Materials by ALD or CVD Processes

In other embodiments, a substrate may be exposed to a series of processsequences to form cobalt-containing contact materials. Generally, thesubstrate is exposed to at least one preclean process prior toperforming at least one deposition process to form and/or deposit acobalt silicide material, a metallic cobalt material, or combinationsthereof on the substrate. The at least one deposition process forforming the cobalt-containing materials preferably an ALD process, a CVDprocess, or combinations thereof, but may also include a PVD process oran electroless deposition process. The ALD and CVD processes includeplasma-enhanced (PE) processes, such as PE-ALD or PE-CVD processes, aswell as pulsed processes, such as a pulsed CVD process or a pulsedPE-CVD process. A metallic contact material is deposited or formed onthe substrate in one or multiple steps (e.g., seed layer, bulk layer, orfill layer). Subsequently, the substrate is exposed to a planarizationprocess to remove any excess metallic contact material on the substratesurface. The substrate may be exposed to at least one annealing processprior to, during, or subsequent to any of the deposition processes.

FIGS. 10-16 and 19 depict flow charts of multiple processes that may beused to fabricate substrate 1700, illustrated in FIGS. 17A-171, asdescribed in embodiments herein. FIGS. 17A-171 illustratecross-sectional views of electronic devices disposed on substrate 1700at different stages of interconnect fabrication sequences incorporatingmultiple embodiments herein. FIGS. 10-16 provide flow charts ofprocesses 1000, 1100, 1200, 1300, 1400, 1500, 1600, and 1900 that may beused to form substrate 1700. In other embodiments, processes 2000, 2100,2200, 2400, and 2600 or steps thereof, as depicted in FIGS. 20-22, 24,and 26, may be used completely or in-part to form substrate 1700 or onother substrates not illustrated herein.

In one embodiment, process 1000 includes exposing substrate 1700 to apreclean process (step 1010), depositing cobalt silicide material 1720on substrate 1700 (step 1020), depositing metallic cobalt material 1730on substrate 1700 (step 1030), depositing metallic contact material 1740on substrate 1700 (step 1040), and exposing substrate 1700 to aplanarization process (step 1050).

In another embodiment, process 1100 includes exposing substrate 1700 toa preclean process (step 1110), depositing cobalt silicide material 1720on substrate 1700 (step 1120), depositing metallic cobalt material 1730on substrate 1700 (step 1130), exposing substrate 1700 to an annealingprocess (step 1140), depositing metallic contact material 1740 onsubstrate 1700 (step 1150), and exposing substrate 1700 to aplanarization process (step 1160).

In another embodiment, process 1200 includes exposing substrate 1700 toa preclean process (step 1210), depositing cobalt silicide material 1720on substrate 1700 (step 1220), exposing substrate 1700 to an annealingprocess (step 1230), depositing metallic cobalt material 1730 onsubstrate 1700 (step 1240), depositing metallic contact material 1740 onsubstrate 1700 (step 1250), and exposing substrate 1700 to aplanarization process (step 1260).

In another embodiment, process 1300 includes exposing substrate 1700 toa preclean process (step 1310), depositing cobalt silicide material 1720on substrate 1700 (step 1320), depositing metallic cobalt material 1730on substrate 1700 (step 1330), depositing metallic contact material 1740on substrate 1700 (step 1340), exposing substrate 1700 to aplanarization process (step 1350), and exposing substrate 1700 to anannealing process (step 1360).

In another embodiment, process 1400 includes exposing substrate 1700 toa preclean process (step 1410), depositing cobalt silicide material 1720on substrate 1700 (step 1420), depositing metallic cobalt material 1730on substrate 1700 (step 1430), depositing metallic contact material 1740on substrate 1700 (step 1440), exposing substrate 1700 to an annealingprocess (step 1450), and exposing substrate 1700 to a planarizationprocess (step 1460).

In another embodiment, process 1500 includes exposing substrate 1700 toa preclean process (step 1510), depositing metallic cobalt material 1715on substrate 1700 (step 1520), exposing substrate 1700 to an annealingprocess to form cobalt silicide material 1720 (step 1530), depositingmetallic cobalt material 1730 on substrate 1700 (step 1540), depositingmetallic contact material 1740 on substrate 1700 (step 1550), andexposing substrate 1700 to a planarization process (step 1560).

In another embodiment, process 1600 includes exposing substrate 1700 toa preclean process (step 1610), depositing metallic cobalt material 1715on substrate 1700 (step 1620), exposing substrate 1700 to an annealingprocess to form cobalt silicide material 1720 (step 1630), depositingmetallic contact material 1740 on substrate 1700 (step 1640), andexposing substrate 1700 to a planarization process (step 1650).

In another embodiment, process 1900 includes exposing substrate 1700 toa preclean process (step 1910), depositing cobalt silicide material 1720on substrate 1700 (step 1920), depositing metallic contact material 1740on substrate 1700 (step 1930), and exposing substrate 1700 to aplanarization process (step 1940).

FIG. 17A illustrates a cross-sectional view of substrate 1700 havingcontact aperture 1710 formed within silicon-containing layer 1702.Contact aperture 1710 has wall surfaces 1712 and bottom surface 1714.Silicon-containing layer 1702 may contain a dielectric material thatincludes silicon, polysilicon, amorphous silicon, epitaxial silicon,silicon dioxide and other silicon oxides, silicon on insulator (SOI),silicon oxynitride, doped variants thereof, fluorine-doped silicateglass (FSG), or carbon-doped silicon oxides, such as SiO_(x)C_(y), forexample, BLACK DIAMOND® low-k dielectric, available from AppliedMaterials, Inc., located in Santa Clara, Calif. Contact aperture 1710may be formed in silicon-containing layer 1702 using conventionallithography and etching techniques to expose bottom surface 1714, suchas a bit line layer. Alternatively, silicon-containing layer 1702 may bedeposited on substrate 1700 forming contact aperture 1710 therein.Silicon-containing layer 1702 and bottom surface 1714 may contain puresilicon or a silicon-containing material that contains germanium,carbon, boron, phosphorous, arsenic, metals, or combinations thereof,among other dopants. For example, bottom surface 1714 may containsilicon, silicon carbide, silicon germanium, silicon germanium carbide,metal silicide, doped variants thereof, or combinations thereof. In oneexample, bottom surface 1714 is a MOS type source or a drain interfaceand is generally a doped (e.g., n+ or p+) silicon region of substrate1700.

Native surface 1704 may contain an oxide layer, a contaminant, orcombinations thereof disposed on substrate 1700. In one example, nativesurface 1704 contains a native oxide layer that is formed upon theoxidation of bottom surface 1714 during an exposure to air subsequent toetching and ashing processes used to form contact aperture 1710. Nativesurface 1704 may be a continuous layer or a discontinuous layer acrossbottom surface 1714 and include surface terminations of oxygen,hydrogen, hydroxide, halide, metals, or combinations thereof. Nativesurface 1704 may also contain various contaminants, such as organic andinorganic residues and particulate. Native surface 1704 formed on bottomsurface 1714 generally contains a metastable lower quality oxide (e.g.,SiO_(x), where x is between 0 and 2) compared to the much more stableoxide materials that are typically used to form silicon-containing layer1702 (e.g., SiO₂), such as thermal oxides. The metastable lower qualityoxide (e.g., the “native oxide”) is much easier to remove from bottomsurface 1714 than silicon-containing layer 1702, probably due to a loweractivation energy than the material of silicon-containing layer 1702.

Pre- and Post Treatment and Soak Processes

FIG. 17B illustrates substrate 1700 containing exposed surface 1706 ofbottom surface 1714 subsequent to the removal of native surface 1704.Exposed surface 1706 may be formed by at least one pretreatment processduring steps 1010, 1110, 1210, 1310, 1410, 1510, and 1610 of processes1000-1600, as described by embodiments herein. In other embodiments,exposed surfaces (e.g., silicon-containing) on other substrates may beformed by at least one pre-treatment process or pre-soak process duringsteps 2210, 2410, 2430, 2450, 2610, and 2630, processes 2200, 2400, and2600, as described herein. A preclean process may be used to removenative surface 1704 and reveal a silicon-containing surface of exposedsurface 1706.

In one embodiment, the preclean process may be a wet clean process, suchas a buffered oxide etch (BOE) process, a SC1 process, a SC2 process, ora HF-last process. Alternatively, the preclean process may be a dryclean process, such as a plasma etch process. For example, a plasma etchprocess that may be used during a preclean process is the SICONI™preclean process, available from Applied Materials, Inc., located inSanta Clara, Calif. Pretreatment processes, such as a preclean processand an activation process for forming exposed surface 1706, are furtherdescribed below. In another embodiment, substrate 1700 is exposed toreducing hydrogen plasma that chemically reduces native surface 1704 toa silicon-containing surface of exposed surface 1706.

Exposed surfaces, such as exposed surface 1706, may be asilicon-containing surface of an underlying material layer or of theactual substrate and include materials of silicon, silicon oxide,silicon germanium, silicon carbon, silicon germanium carbon, derivativesthereof, doped derivatives, or combinations thereof. The exposedsurfaces may be crystalline, polycrystalline, or amorphous. In oneexample, an exposed surface may be a crystalline surface of the actualunderlying silicon substrate. In another example, an exposed surface maybe an epitaxially deposited silicon-containing material. In anotherexample, an exposed surface may be a polycrystalline silicon-containingmaterial. In another example, an exposed surface may be a silicon oxideor silicon oxynitride material.

Throughout the application, the terms “silicon-containing” materials,films, or layers should be construed to include a composition containingat least silicon and may contain germanium, carbon, oxygen, boron,arsenic, and/or phosphorus. Other elements, such as metals, halogens orhydrogen may be incorporated within a silicon-containing material, filmor layer, usually as impurities.

Wet Clean Processes

In one embodiment, substrate 1700 may be exposed to a wet clean processto remove native surface 1704 and to form exposed surface 1714 duringsteps 1010, 1110, 1210, 1310, 1410, 1510, 1610, and 1910. In anotherembodiment, other substrates (not shown) may be exposed to a wet cleanprocess to remove any native surfaces and to form exposed surfacesduring steps 2210, 2410, and 2610 in processes 2200, 2400, and 2600.Substrate 1700 may be treated by wet clean processes, such as an acidiccleaning process (e.g., a solution containing hydrochloric acid andhydrogen peroxide held at elevated temperature, such as SC2 clean), abasic cleaning process (e.g., a solution containing ammonium hydroxideand hydrogen peroxide held at elevated temperature, such as SC1 clean),or a series of wet cleans containing both acidic and basic cleaningprocesses. In a preferred embodiment, substrate 1700 is exposed to a SC1solution (e.g., TMAH and H₂O₂) to remove organic residues and othercontaminants and subsequently, exposed to a BOE solution (e.g., 0.5 M ofTEA-HF solution) to remove native oxides.

A wet clean process may include dispensing a wet clean solution acrossor sprayed on the surface of substrate 1700. The wet clean process maybe an in situ process performed in the same processing cell as asubsequent electroless deposition process. Alternatively, substrate 1700may be wet cleaned in a separate processing cell from the subsequentelectroless deposition processing cell. A wet-clean pretreatment processmay occur for about 10 minutes or less, such as within a range fromabout 5 seconds to about 5 minutes, preferably, from about 5 seconds toabout 3 minutes, more preferably, from about 10 seconds to about 2minutes, and more preferably, from about 15 seconds to about 1 minute.During the pretreatment process, the substrate is maintained at atemperature within a range from about 15° C. to about 50° C.,preferably, about room temperature (e.g., 20° C.). The wet-clean processmay be performed in a TEMPEST™ wet-clean system, available from AppliedMaterials, Inc., located in Santa Clara, Calif. Other examples ofvarious wet-clean processes that may be used to remove native surface1704 are further described in commonly assigned U.S. Ser. No. 11/385,484(APPM/9916.05), filed Mar. 20, 2006, and published as US 2006-0251801,U.S. Ser. No. 11/385,344 (APPM/9916.03), filed Mar. 20, 2006, andpublished as US 2006-0251800, and U.S. Ser. No. 11/385,290 (APPM/9916),filed Mar. 20, 2006, and published as US 2006-0252252, which are allincorporated by reference herein in their entirety.

In one embodiment, native surface 1704 may be removed by a HF-lastsolution to form exposed surface 1714 as a substantially oxide-free,silicon hydride surface. In one example, the wet-clean process utilizesan HF-last solution containing water, HF and optional additivesincluding chelators, surfactants, reductants, other acids orcombinations thereof. In one example, the hydrogen fluorideconcentration of a wet-clean solution may be within a range from about10 ppm to about 5 wt %, preferably, from about 50 ppm to about 2 wt %,and more preferably, from about 100 to about 1 wt %, for example, about0.5 wt %. In another embodiment, native surface 1704 is removed during aliquid reduction process to form exposed surface 1714 as a substantiallyoxide-free, silicon-containing surface.

SC1 and SC2 Processes

In one embodiment, substrate 1700 containing native surface 1704 may beexposed to a SC1 clean solution to remove contaminants, such as organicand inorganic residues and particulates while forming exposed surface1706 during steps 1010, 1110, 1210, 1310, 1410, 1510, and 1610. Inanother embodiment, other substrates (not shown) may be exposed to a SC1clean solution to remove contaminants, such as organic and inorganicresidues and particulates while forming exposed surface during steps2210, 2410, and 2610. In one example, the SC1 clean solution containshydrogen peroxide and at least one basic compound, such as ammoniumhydroxide, tetramethylammonium hydroxide, ethanolamine, diethanolamine,triethanolamine, derivatives thereof, salts thereof, or combinationsthereof. The substrate may be heated to a temperature within a rangefrom about 50° C. to about 100° C., preferably, from about 70° C. toabout 90° C.

In another embodiment, substrate 1700 containing native surface 1704 maybe exposed to a SC2 clean solution during steps 1010, 1110, 1210, 1310,1410, 1510, and 1610. In another embodiment, other substrates (notshown) may be exposed to a SC2 clean solution during steps 2210, 2410,and 2610. In one example, the SC2 clean solution contains hydrogenperoxide and hydrogen chloride. The substrate may be heated to atemperature within a range from about 50° C. to about 100° C.,preferably, from about 70° C. to about 90° C.

BOE Processes and Solutions

In another embodiment of a preclean process, buffered oxide etch (BOE)solutions and processes may be used to selectively remove native oxidesand other contaminants from substrate 1700 during steps 1010, 1110,1210, 1310, 1410, 1510, 1610, and 1910. Also, other substrates may beused to selectively remove native oxides and other contaminants from thesubstrate during steps 2210, 2410, and 2610. The BOE solutions generallycontain an alkylamine compound or an alkanolamine compound and anetchant, such as hydrogen fluoride. The alkanolamine compounds mayinclude ethanolamine (EA), diethanolamine (DEA), triethanolamine (TEA),or derivatives thereof. In one example, native surface 1704 may beremoved to form exposed surface 1714 by exposing substrate 1700 to a BOEsolution containing about 0.5 M of TEA-HF solution for about 25 secondsat about 20° C. In another example, substrate 1700 may be exposed to aBOE solution containing about 0.5 M of EA-HF solution for about 20seconds at about 20° C. In another example, substrate 1700 may beexposed to a BOE solution containing about 0.5 M of DEA-HF solution forabout 30 seconds at about 20° C. Other examples of BOE wet-cleanprocesses that may be used to remove native surface 1704 are furtherdescribed in commonly assigned U.S. Ser. No. 11/385,041, filed Mar. 20,2006, which is herein incorporated by reference in its entirety.

Plasma Etch Process

In another embodiment, substrate 1700 may be exposed to a plasma etchprocess or a plasma clean process remove native surface 1704 and to formexposed surface 1714 during steps 1010, 1110, 1210, 1310, 1410, 1510,1610, and 1910. In another embodiment, other substrates may be exposedto a plasma etch process or a plasma clean process remove any nativesurfaces and to form an exposed surface during steps 2210, 2410, and2610. Also, the plasma etch process may be used to remove native oxidesand other contaminants formed on exposed contact surfaces prior toseveral processes described herein, such as an electroless depositionprocess. Surfaces exposed to the plasma etch process usually have animprove adhesion of subsequently deposited metal layers. The plasma etchprocess is performed in a chamber adapted to perform a chemical etchclean and in-situ anneal on substrates.

An exemplary plasma etch process for removing native oxides on a surfaceof the substrate using an ammonia (NH₃) and nitrogen trifluoride (NF₃)gas mixture performed within a plasma etch processing chamber will nowbe described. The plasma etch process begins by placing a substrate intoa plasma etch processing chamber. During processing, the substrate maybe cooled below 65° C., such as between 15° C. and 50° C. In anotherexample, the substrate is maintained at a temperature of between 22° C.and 40° C. Typically, the substrate support is maintained below about22° C. to reach the desired substrate temperatures.

The ammonia gas and nitrogen trifluoride gas are introduced into the dryetching chamber to form a cleaning gas mixture. The amount of each gasintroduced into the chamber is variable and may be adjusted toaccommodate, for example, the thickness of the oxide layer to beremoved, the geometry of the substrate being cleaned, the volumecapacity of the plasma and the volume capacity of the chamber body. Inone aspect, the gases are added to provide a gas mixture having at leasta 1:1 molar ratio of ammonia to nitrogen trifluoride. In another aspect,the molar ratio of the gas mixture is at least about 3 to about 1(ammonia to nitrogen trifluoride). Preferably, the gases are introducedin the dry etching chamber at a molar ratio of from about 1:1 (ammoniato nitrogen trifluoride) to about 30:1, more preferably, from about 5:1(ammonia to nitrogen trifluoride) to about 30:1. More preferably, themolar ratio of the gas mixture is of from about 5 to 1 (ammonia tonitrogen trifluoride) to about 10 to about 1. The molar ratio of the gasmixture may also fall between about 10:1 (ammonia to nitrogentrifluoride) and about 20:1. Alternatively, a pre-mixed gas mixture ofthe preferred molar ratio may be used during the plasma etch process.

A purge gas or carrier gas may also be added to the gas mixture. Anysuitable purge/carrier gas may be used, such as argon, helium, hydrogen,nitrogen, forming gas, or mixtures thereof. Typically, the overall gasmixture by volume of ammonia and nitrogen trifluoride is within a rangefrom about 0.05% to about 20%. The remainder of the process gas may bethe carrier gas. In one embodiment, the purge or carrier gas is firstintroduced into the chamber body before the reactive gases to stabilizethe pressure within the chamber body.

The operating pressure within the chamber body can be variable. Thepressure may be maintained within a range from about 500 mTorr to about30 Torr, preferably, from about 1 Torr to about 10 Torr, and morepreferably, from about 3 Torr to about 6 Torr. An RF power within arange from about 5 watts to about 600 watts may be applied to ignite aplasma of the gas mixture within the plasma cavity. Preferably, the RFpower is less than about 100 watts. More preferable is that thefrequency at which the power is applied is very low, such as less thanabout 100 kHz, and more preferably, within a range from about 50 kHz toabout 90 kHz.

The plasma energy dissociates the ammonia and nitrogen trifluoride gasesinto reactive species that combine to form a highly reactive ammoniafluoride (NH₄F) compound and/or ammonium hydrogen fluoride (NH₄F—HF)which reacts with the substrate surface. In one embodiment, the carriergas is first introduced into the dry etch chamber, a plasma of thecarrier gas is generated, and then the reactive gases, ammonia andnitrogen trifluoride, are added to the plasma.

Not wishing to be bound by theory, it is believed that the etchant gas,NH₄F and/or NH₄F—HF, reacts with the native oxide surface to formammonium hexafluorosilicate ((NH₄)₂SiF₆), ammonia, and water. Theammonia and water are vapors at processing conditions and removed fromthe chamber by a vacuum pump attached to the chamber. A thin film ofammonium hexafluorosilicate is left behind on the substrate surface.

The thin film of ammonium hexafluorosilicate on the substrate surfacemay be removed during a vacuum sublimation process. The process chamberradiates heat to dissociate or sublimate the thin film of ammoniumhexafluorosilicate into volatile SiF₄, NH₃, and HF products. Thesevolatile products are then removed from the chamber by the vacuum pumpattached to the system. In one example, a temperature of about 75° C. orhigher is used to effectively sublimate and remove the thin film fromthe substrate. Preferably, a temperature of about 100° C. or higher isused, such a temperature within a range from about 115° C. to about 200°C. Once the film has been removed from the substrate, the chamber ispurged and evacuated prior to removing the cleaned substrate.

A plasma cleaning processes may be performed using a vacuum precleanchamber, such as a SICONI™ Preclean chamber and process, both availablefrom Applied Materials, Inc., located in Santa Clara, Calif. Furtherdescription of a plasma-assisted dry etch chamber and plasma etchprocess that may be used by embodiment herein is disclosed in commonlyassigned U.S. Ser. No. 11/063,645 (APPM/8802), filed on Feb. 22, 2005,and published as US 2005-0230350, and U.S. Ser. No. 11/192,993(APPM/8707), filed on Jul. 29, 2005, and published as US 2006-0033678which are hereby incorporated by reference in their entirety to theextent not inconsistent with the claimed invention.

Inert Plasma Process

In another embodiment, substrate 1700 containing native surface 1704 maybe exposed to an inert plasma process to remove contaminants, such asorganic and inorganic residues and particulates while forming exposedsurface 1706 during steps 1010, 1110, 1210, 1310, 1410, 1510, 1610, and1910. In another embodiment, other substrates containing a nativesurface may be exposed to an inert plasma process to removecontaminants, such as organic and inorganic residues and particulateswhile forming an exposed surface during steps 2210, 2410, and 2610. Inone example, the inert plasma preclean is the Ar+ Preclean Process,available from Applied Materials, Inc., located in Santa Clara, Calif.Substrate 1700 may be transferred into a plasma chamber, such as theCENTURA® DPN chamber, available from Applied Materials, Inc., located inSanta Clara, Calif. In one aspect, the plasma chamber is on the samecluster tool as the ALD chamber or the CVD chamber used to depositcobalt silicide material 1720 or metallic cobalt material 1715 or 1730.Therefore, substrate 1700 may be exposed to an inert plasma processwithout being exposed to the ambient environment. During the inertplasma process, native surface 1704 is bombarded with ionic argon formedby flowing argon into the DPN chamber. Gases that may be used in aninert plasma process include argon, helium, neon, xenon, or combinationsthereof.

The inert plasma process proceeds for a time period from about 10seconds to about 5 minutes, preferably, from about 30 seconds to about 4minutes, and more preferably, from about 1 minute to about 3 minutes.Also, the inert plasma process is conducted at a plasma power settingwithin a range from about 500 watts to about 3,000 watts, preferablyfrom about 700 watts to about 2,500 watts, and more preferably fromabout 900 watts to about 1,800 watts. Generally, the plasma process isconducted with a duty cycle of about 50% to about 100% and a pulsefrequency at about 10 kHz. The plasma chamber may have a pressure withina range from about 10 mTorr to about 80 mTorr. The inert gas may have aflow rate within a range from about 10 standard cubic centimeters perminute (sccm) to about 5 standard liters per minute (slm), preferablyfrom about 50 sccm to about 750 sccm, and more preferably from about 100sccm to about 500 sccm. In a preferred embodiment, the inert plasmaprocess is a nitrogen free argon plasma produced in a plasma chamber.

Deposition of Cobalt-containing Materials

FIGS. 17C-17E illustrate substrate 1700 having cobalt-containingmaterials deposited and/or formed thereon, as described by embodimentsherein. The cobalt-containing materials include cobalt silicide material1720, metallic cobalt material 1715, and/or metallic cobalt material1730 and may be deposited or formed by an ALD process, a CVD process, aPVD process, an electroless deposition process, or combinations thereof.

In one embodiment, process 1000 includes depositing cobalt silicidematerial 1720 onto substrate 1700 (step 1020) and depositing metalliccobalt material 1730 onto substrate 1700 (step 1030), as depicted inFIGS. 17D and 17E. In one example, cobalt silicide material 1720 andmetallic cobalt material 1730 are deposited in the same processingchamber, such as an ALD chamber, a CVD chamber, or a PVD chamber. Inanother example, cobalt silicide material 1720 and metallic cobaltmaterial 1730 are deposited in the separate processing chambers, such asan ALD chamber, a CVD chamber, or a PVD chamber.

In another embodiment, process 1100 includes depositing cobalt silicidematerial 1720 onto substrate 1700 (step 1120), depositing metalliccobalt material 1730 onto substrate 1700 (step 1130), and exposingsubstrate 1700 to an annealing process (step 1140), as depicted in FIGS.17D and 17E. In one example, cobalt silicide material 1720 and metalliccobalt material 1730 are deposited and the annealing process isconducted within the same processing chamber, such as an ALD chamber, aCVD chamber, or a PVD chamber. In another example, cobalt silicidematerial 1720 and metallic cobalt material 1730 are deposited in thesame processing chamber and the annealing process is conducted in anannealing chamber. In another example, cobalt silicide material 1720 andmetallic cobalt material 1730 are deposited in the separate processingchambers, such as an ALD chamber, a CVD chamber, or a PVD chamber andthe annealing process is conducted in either of the processing chambers.In another example, cobalt silicide material 1720 and metallic cobaltmaterial 1730 are deposited in the separate processing chambers, such asan ALD chamber, a CVD chamber, or a PVD chamber and the annealingprocess is conducted in an annealing chamber.

In another embodiment, process 1200 includes depositing cobalt silicidematerial 1720 onto substrate 1700 (step 1220), exposing substrate 1700to an annealing process (step 1230), and depositing metallic cobaltmaterial 1730 onto substrate 1700 (step 1240), as depicted in FIGS. 17Dand 17E. In one example, cobalt silicide material 1720 and metalliccobalt material 1730 are deposited and the annealing process isconducted within the same processing chamber, such as an ALD chamber, aCVD chamber, or a PVD chamber. In another example, cobalt silicidematerial 1720 and metallic cobalt material 1730 are deposited in thesame processing chamber and the annealing process is conducted in anannealing chamber. In another example, cobalt silicide material 1720 andmetallic cobalt material 1730 are deposited in the separate processingchambers, such as an ALD chamber, a CVD chamber, or a PVD chamber andthe annealing process is conducted in either of the processing chambers.In another example, cobalt silicide material 1720 and metallic cobaltmaterial 1730 are deposited in the separate processing chambers, such asan ALD chamber, a CVD chamber, or a PVD chamber and the annealingprocess is conducted in an annealing chamber.

In another embodiment, process 1300 includes depositing cobalt silicidematerial 1720 onto substrate 1700 (step 1320), depositing metalliccobalt material 1730 onto substrate 1700 (step 1330), as depicted inFIGS. 17D and 17E. Subsequently, substrate 1700 is exposed to anannealing process (step 1360). In one example, cobalt silicide material1720 and metallic cobalt material 1730 are deposited and the annealingprocess is conducted within the same processing chamber, such as an ALDchamber, a CVD chamber, or a PVD chamber. In another example, cobaltsilicide material 1720 and metallic cobalt material 1730 are depositedin the same processing chamber and the annealing process is conducted inan annealing chamber. In another example, cobalt silicide material 1720and metallic cobalt material 1730 are deposited in the separateprocessing chambers, such as an ALD chamber, a CVD chamber, or a PVDchamber and the annealing process is conducted in either of theprocessing chambers. In another example, cobalt silicide material 1720and metallic cobalt material 1730 are deposited in the separateprocessing chambers, such as an ALD chamber, a CVD chamber, or a PVDchamber and the annealing process is conducted in an annealing chamber.

In another embodiment, process 1400 includes depositing cobalt silicidematerial 1720 onto substrate 1700 (step 1420), depositing metalliccobalt material 1730 onto substrate 1700 (step 1430), as depicted inFIGS. 17D and 17E. Subsequently, substrate 1700 is exposed to anannealing process (step 1450). In one example, cobalt silicide material1720 and metallic cobalt material 1730 are deposited and the annealingprocess is conducted within the same processing chamber, such as an ALDchamber, a CVD chamber, or a PVD chamber. In another example, cobaltsilicide material 1720 and metallic cobalt material 1730 are depositedin the same processing chamber and the annealing process is conducted inan annealing chamber. In another example, cobalt silicide material 1720and metallic cobalt material 1730 are deposited in the separateprocessing chambers, such as an ALD chamber, a CVD chamber, or a PVDchamber and the annealing process is conducted in either of theprocessing chambers. In another example, cobalt silicide material 1720and metallic cobalt material 1730 are deposited in the separateprocessing chambers, such as an ALD chamber, a CVD chamber, or a PVDchamber and the annealing process is conducted in an annealing chamber.

In another embodiment, process 1500 includes depositing metallic cobaltmaterial 1715 onto substrate 1700 (step 1520) and exposed to anannealing process (step 1530) to form cobalt silicide material 1720during a salicide process or a silicidation process, as depicted inFIGS. 17C and 17D. In one aspect, metallic cobalt material 1715 may becompletely consumed to form cobalt silicide material 1720 during thesalicide process or the silicidation process. Cobalt silicide material1720 is formed from silicon atoms of the exposed surface 1706 and cobaltatoms of metallic cobalt material 1715. Thereafter, metallic cobaltmaterial 1730 may be deposited onto substrate 1700 (step 1540), asdepicted in FIG. 17E.

In another embodiment, process 1500 includes depositing metallic cobaltmaterial 1715 onto substrate 1700 (step 1520) and exposed to anannealing process (step 1530) to form cobalt silicide material 1720 fromonly a portion of metallic cobalt material 1715 during a salicide orsilicidation process, as depicted in FIGS. 17C and 17E. Metallic cobaltmaterial 1715 is only partially consumed to form cobalt silicidematerial 1720 while the remaining portion stays metallic cobalt.Therefore, the remaining portion of metallic cobalt material 1715 afterthe salicide or silicidation process is metallic cobalt material 1730,as depicted in FIG. 17E. Optionally, additional metallic cobalt material1730 may be deposited onto substrate 1700 (step 1540).

In one example, metallic cobalt material 1715 is deposited and theannealing process is conducted within the same processing chamber, suchas an ALD chamber, a CVD chamber, or a PVD chamber. In another example,metallic cobalt material 1715 is deposited in a processing chamber andthe annealing process is conducted in an annealing chamber. In anotherexample, metallic cobalt material 1715 and metallic cobalt material 1730are deposited in the separate processing chambers, such as an ALDchamber, a CVD chamber, or a PVD chamber and the annealing process isconducted in either of the processing chambers. In another example,metallic cobalt material 1715 and metallic cobalt material 1730 aredeposited in the separate processing chambers, such as an ALD chamber, aCVD chamber, or a PVD chamber and the annealing process is conducted inan annealing chamber.

In another embodiment, process 1600 includes depositing metallic cobaltmaterial 1715 onto substrate 1700 (step 1620) and exposed to anannealing process (step 1630) to form cobalt silicide material 1720during a salicide or silicidation process, as depicted in FIGS. 17C and17D. In one aspect, metallic cobalt material 1715 may be completelyconsumed to form cobalt silicide material 1720 during the salicideprocess or the silicidation process (FIG. 17D). In another aspect,metallic cobalt material 1715 is only partial consumed to form cobaltsilicide material 1720 while the remaining portion of metallic cobaltmaterial 1715 is depicted as metallic cobalt material 1730 (FIG. 17E).In one example, metallic cobalt material 1715 is deposited and theannealing process is conducted within the same processing chamber, suchas an ALD chamber, a CVD chamber, or a PVD chamber. In another example,metallic cobalt material 1715 is deposited in a processing chamber andthe annealing process is conducted in an annealing chamber.

In one embodiment, process 1900 includes depositing cobalt silicidematerial 1720 onto substrate 1700 (step 1920), as depicted in FIG. 17D.Cobalt silicide material 1720 may be deposited in an ALD chamber, a CVDchamber, or a PVD chamber.

Deposition of Cobalt Silicide and Metallic Cobalt Materials

FIG. 18 shows an integrated multi-chamber substrate processing systemsuitable for performing at least one embodiment of the deposition andannealing processes described herein. The preclean, deposition, andannealing processes may be performed in a multi-chamber processingsystem or cluster tool having at least one ALD chamber, at least one CVDchamber, at least one PVD chamber, or at least one annealing chamberdisposed thereon. A processing platform that may be used to duringprocesses described herein is an ENDURA® processing platformcommercially available from Applied Materials, Inc., located in SantaClara, Calif.

FIG. 18 is a schematic top view of one embodiment of a processingplatform system 1835 including two transfer chambers 1848 and 1850,transfer robots 1849 and 1851, disposed within transfer chambers 1848and 1850 respectfully, and a plurality of processing chambers 1836,1838, 1840, 1841, 1842, and 1843, disposed on the two transfer chambers1848 and 1850. The first transfer chamber 1848 and the second transferchamber 1850 are separated by pass-through chambers 1852, which maycomprise cool-down or pre-heating chambers. Pass-through chambers 1852also may be pumped down or ventilated during substrate handling when thefirst transfer chamber 1848 and the second transfer chamber 1850 operateat different pressures. For example, the first transfer chamber 1848 mayoperate at a pressure within a range from about 100 milliTorr to about 5Torr, such as about 400 milliTorr, and the second transfer chamber 1850may operate at a pressure within a range from about 1×10⁻⁸ Torr to about1×10⁻⁸ Torr, such as about 1×10⁻⁷ Torr. Processing platform system 1835is automated by programming a microprocessor controller 1854. Thesubstrates may be transferred between various chambers within processingplatform system 1835 without breaking a vacuum or exposing thesubstrates to other external environmental conditions.

The first transfer chamber 1848 may be coupled with two degas chambers1844, two load lock chambers 1846, and pass-through chambers 1852. Thefirst transfer chamber 1848 may also have reactive preclean chamber 1842and chamber 1836, may be an ALD process chamber or a CVD chamber. Thepreclean chamber 1842 may be a PreClean II chamber, commerciallyavailable from Applied Materials, Inc., of Santa Clara, Calif.Substrates (not shown) are loaded into processing platform system 1835through load-lock chambers 1846. Thereafter, the substrates aresequentially degassed and cleaned in degas chambers 1844 and thepreclean chamber 1842, respectively. The transfer robot 1849 moves thesubstrate between the degas chambers 1844 and the preclean chamber 1842.The substrate may then be transferred into chamber 1836. In oneembodiment, degas chambers 1844 may be used during the annealingprocesses described herein.

The second transfer chamber 1850 is coupled to a cluster of processchambers 1838, 1840, 1841, and 1843. In one example, chambers 1838 and1840 may be ALD chambers for depositing materials, such as cobaltsilicide, metallic cobalt, or tungsten, as desired by the operator. Inanother example, chambers 1838 and 1840 may be CVD chambers fordepositing materials, such as tungsten, as desired by the operator. Anexample of a suitable CVD chamber includes WXZ™ chambers, commerciallyavailable from Applied Materials, Inc., located in Santa Clara, Calif.The CVD chambers may be adapted to deposit materials by ALD techniquesas well as by conventional CVD techniques. Chambers 1841 and 1843 may berapid thermal annealing (RTA) chambers, or rapid thermal process (RTP)chambers, that may be used to anneal substrates at low or extremely lowpressures. An example of an RTA chamber is a RADIANCE® chamber,commercially available from Applied Materials, Inc., Santa Clara, Calif.Alternatively, the chambers 1841 and 1843 may be WXZ™ depositionchambers capable of performing high temperature CVD deposition,annealing processes, or in situ deposition and annealing processes. ThePVD processed substrates are moved from transfer chamber 1848 intotransfer chamber 1850 via pass-through chambers 1852. Thereafter,transfer robot 1851 moves the substrates between one or more of theprocess chambers 1838, 1840, 1841, and 1843 for material deposition andannealing as required for processing.

RTA chambers (not shown) may also be disposed on the first transferchamber 1848 of processing platform system 1835 to provide postdeposition annealing processes prior to substrate removal fromprocessing platform system 1835 or transfer to the second transferchamber 1850. In one example, the substrate may be transferred betweenchambers within processing platform system 1835 without a vacuum break.

While not shown, a plurality of vacuum pumps is disposed in fluidcommunication with each transfer chamber and each of the processingchambers to independently regulate pressures in the respective chambers.The pumps may establish a vacuum gradient of increasing pressure acrossthe apparatus from the load lock chamber to the processing chambers.

Alternatively, a plasma etch chamber, such as a DPS® (decoupled plasmasource) chamber manufactured by Applied Materials, Inc., of Santa Clara,Calif., may be coupled to processing platform system 1835 or in aseparate processing system for etching the substrate surface to removeexcess material after a vapor deposition process, annealing thedeposited cobalt-containing material, or forming a silicide during asalicide process. For example in forming cobalt silicide from cobalt andsilicon material by an annealing process, the etch chamber may be usedto remove excess cobalt material from the substrate surface. Embodimentsof the invention also contemplate the use of other etch processes andapparatus, such as a wet etch chamber, used in conjunction with theprocess and apparatus described herein.

In one embodiment, substrate 1700 may initially be exposed to adegassing process for about 5 minutes or less, for example, about 1minute, while heating substrate 1700 to a temperature within a rangefrom about 250° C. to about 400° C., for example, about 350° C. Thedegassing process may further include maintaining the substrate in areduced vacuum at a pressure in the range from about 1×10⁻⁷ Torr toabout 1×10⁻⁵ Torr, for example, about 5×10⁻⁶ Torr. The degassing processremoves volatile surface contaminants, such as water vapor, solvents orvolatile organic compounds.

Cobalt silicide material 1720 may be formed using a CVD process, an ALDprocess, or combinations thereof, as described herein (FIG. 17D).Generally, a single cycle of the ALD process includes sequentiallyexposing substrate 1700 to a cobalt precursor and a silicon precursor toform cobalt silicide material 1720. The ALD cycle is repeated untilcobalt silicide material 1720 has a desired thickness.

The thickness for cobalt silicide material 1720 is variable depending onthe device structure to be fabricated. In one embodiment, the thicknessof cobalt silicide material 1720 is less than about 300 Å, preferably,within a range from about 5 Å to about 200 Å, more preferably, fromabout 10 Å to about 100 Å, more preferably, from about 15 Å to about 50Å, and more preferably, from about 25 Å to about 30 Å. Metallic cobaltmaterials 1715 or 1730 may have a film thickness within a range fromabout 5 Å to about 300 Å, preferably, from about 10 Å to about 100 Å,more preferably, from about 20 Å to about 70 Å, and more preferably,from about 40 Å to about 50 Å, for example, about 45 Å.

In one embodiment, the ALD chamber or substrate 1700 may be heated to atemperature of less than about 500° C., preferably within a range fromabout 100° C. to about 450° C., and more preferably, from about 150° C.to about 400° C., for example, about 300° C. The relatively lowdeposition temperature is highly advantageous since as mentionedpreviously, the risk of device damage, particularly where low-kmaterials are employed, rises significantly as temperatures are aboveabout 400° C.

Cobalt-containing Materials by CVD or ALD

Embodiments of the invention provide a method to depositcobalt-containing materials on a substrate by various vapor depositionprocesses, such as ALD, plasma-enhanced ALD (PE-ALD), CVD, andplasma-enhanced CVD (PE-CVD). The plasma-enhanced processes may generatea plasma in situ or by a remote plasma source (RPS). Cobalt-containingmaterials include cobalt silicide material 1720 and metallic cobaltmaterials 1715 and 1730, as described herein. In one embodiment, thecobalt-containing material is deposited on a substrate by sequentiallyexposing the substrate to a reagent and a cobalt precursor during an ALDprocess. In one embodiment, a silicon precursor is used as the reagentto form cobalt silicide material 1720 as a cobalt-containing material.In another embodiment, at least one reducing agent is used as thereagent to form metallic cobalt materials 1715 and 1730 as acobalt-containing material.

In one embodiment, a cobalt-containing material may be formed during aPE-ALD process containing a constant flow of a reagent gas whileproviding sequential pulses of a cobalt precursor and a plasma. Inanother embodiment, a cobalt-containing material may be formed duringanother PE-ALD process that provides sequential pulses of a cobaltprecursor and a reagent plasma. In both of these embodiments, thereagent is generally ionized during the process. Also, the PE-ALDprocess provides that the plasma may be generated external from theprocess chamber, such as by a RPS system, or preferably, the plasma maybe generated in situ a plasma capable ALD process chamber. During PE-ALDprocesses, a plasma may be generated from a microwave (MW) frequencygenerator or a radio frequency (RF) generator. In a preferred example,an in situ plasma is generated by a RF generator. In another embodiment,a cobalt-containing material may be formed during a thermal ALD processthat provides sequential pulses of a cobalt precursor and a reagent.

An ALD process chamber used during embodiments described herein isavailable from Applied Materials, Inc., located in Santa Clara, Calif. Adetailed description of an ALD process chamber may be found in commonlyassigned U.S. Pat. Nos. 6,916,398 and 6,878,206, commonly assigned U.S.Ser. No. 10/281,079, filed on Oct. 25, 2002, and published as US2003-0121608, and commonly assigned U.S. Ser. Nos. 11/556,745 (10429),11/556,752 (10429.02), 11/556,756 (10429.03), 11/556,758 (10429.04),11/556,763 (10429.05), each entitled “Apparatus and Process forPlasma-Enhanced Atomic Layer Deposition,” and each filed Nov. 6, 2006,which are hereby incorporated by reference in their entirety. In anotherembodiment, a chamber configured to operate in both an ALD mode as wellas a conventional CVD mode may be used to deposit cobalt-containingmaterials is described in commonly assigned U.S. Ser. No. 10/712,690(APPM/6766), filed on Nov. 13, 2003, and issued as U.S. Pat. No.7,204,886, which is incorporated herein by reference in its entirety. Adetailed description of an ALD process for forming cobalt-containingmaterials is further disclosed in commonly assigned U.S. Ser. No.10/443,648 (5975), filed on May 22, 2003, and published as US2005-0220998, and commonly assigned U.S. Ser. No. 10/634,662 (5975.P1),filed Aug. 4, 2003, and published as US 2004-0105934, which are herebyincorporated by reference in their entirety. In other embodiments, achamber configured to operate in both an ALD mode as well as aconventional CVD mode that may be used to deposit cobalt-containingmaterials is the TXZ showerhead and CVD chamber available from AppliedMaterials, Inc., located in Santa Clara, Calif.

The process chamber may be pressurized during the ALD process at apressure within a range from about 0.1 Torr to about 80 Torr, preferablyfrom about 0.5 Torr to about 10 Torr, and more preferably, from about 1Torr to about 5 Torr. Also, the chamber or the substrate may be heatedto a temperature of less than about 500° C., preferably within a rangefrom about 100° C. to about 450° C., and more preferably, from about150° C. to about 400° C., for example, about 300° C. During PE-ALDprocesses, a plasma is ignited within the process chamber for an in situplasma process, or alternative, may be formed by an external source,such as a RPS system. A plasma may be generated a MW generator, butpreferably by a RF generator. The RF generator may be set at a frequencywithin a range from about 100 kHz to about 60 MHz. In one example, a RFgenerator, with a frequency of 13.56 MHz, may be set to have a poweroutput within a range from about 100 watts to about 1,000 watts,preferably, from about 250 watts to about 600 watts, and morepreferably, from about 300 watts to about 500 watts. In one example, aRF generator, with a frequency of 400 kHz, may be set to have a poweroutput within a range from about 200 watts to about 2,000 watts,preferably, from about 500 watts to about 1,500 watts. A surface ofsubstrate may be exposed to a plasma having a power per surface areavalue within a range from about 0.01 watts/cm² to about 10.0 watts/cm²,preferably, from about 0.05 watts/cm² to about 6.0 watts/cm².

The substrate may be for example, a silicon substrate having aninterconnect pattern defined in one or more dielectric material layersformed thereon. In one example, the substrate contains a dielectricsurface. The process chamber conditions such as, the temperature andpressure, are adjusted to enhance the adsorption of the process gases onthe substrate so as to facilitate the reaction of the pyrrolyl cobaltprecursors and the reagent gas.

In one embodiment, the substrate may be exposed to a reagent gasthroughout the whole ALD cycle. The substrate may be exposed to a cobaltprecursor gas formed by passing a carrier gas (e.g., nitrogen or argon)through an ampoule of a cobalt precursor. The ampoule may be heateddepending on the cobalt precursor used during the process. In oneexample, an ampoule containing a cobalt carbonyl compound (e.g.,(CO)_(x)Co_(y)L_(z)—where X, Y, Z, and L are described herein) or anamido cobalt compound (e.g., (RR′N)_(x)Co) may be heated to atemperature within a range from about 30° C. to about 500° C. The cobaltprecursor gas usually has a flow rate within a range from about 100 sccmto about 2,000 sccm, preferably, from about 200 sccm to about 1,000sccm, and more preferably, from about 300 sccm to about 700 sccm, forexample, about 500 sccm. The cobalt precursor gas and the reagent gasmay be combined to form a deposition gas. A reagent gas usually has aflow rate within a range from about 100 sccm to about 3,000 sccm,preferably, from about 200 sccm to about 2,000 sccm, and morepreferably, from about 500 sccm to about 1,500 sccm. In one example,silane is used as a reagent gas with a flow rate of about 1,500 sccm.The substrate may be exposed to the cobalt precursor gas or thedeposition gas containing the cobalt precursor and the reagent gas for atime period within a range from about 0.1 seconds to about 8 seconds,preferably, from about 1 second to about 5 seconds, and more preferably,from about 2 seconds to about 4 seconds. The flow of the cobaltprecursor gas may be stopped once the cobalt precursor is adsorbed onthe substrate. The cobalt precursor may be a discontinuous layer,continuous layer or even multiple layers.

The substrate and chamber may be exposed to a purge step after stoppingthe flow of the cobalt precursor gas. The flow rate of the reagent gasmay be maintained or adjusted from the previous step during the purgestep. Preferably, the flow of the reagent gas is maintained from theprevious step. Optionally, a purge gas may be administered into theprocess chamber with a flow rate within a range from about 100 sccm toabout 2,000 sccm, preferably, from about 200 sccm to about 1,000 sccm,and more preferably, from about 300 sccm to about 700 sccm, for example,about 500 sccm. The purge step removes any excess cobalt precursor andother contaminants within the process chamber. The purge step may beconducted for a time period within a range from about 0.1 seconds toabout 8 seconds, preferably, from about 1 second to about 5 seconds, andmore preferably, from about 2 seconds to about 4 seconds. The carriergas, the purge gas and the process gas may contain nitrogen, hydrogen,argon, neon, helium, or combinations thereof. In a preferred embodiment,the carrier gas contains nitrogen.

Thereafter, the flow of the reagent gas may be maintained or adjustedbefore igniting a plasma. The substrate may be exposed to the plasma fora time period within a range from about 0.1 seconds to about 20 seconds,preferably, from about 1 second to about 10 seconds, and morepreferably, from about 2 seconds to about 8 seconds. Thereafter, theplasma power was turned off. In one example, the reagent may be silane,nitrogen, hydrogen or a combination thereof to form a silane plasma, anitrogen plasma, a hydrogen plasma, or a combined plasma. The reactantplasma reacts with the adsorbed cobalt precursor on the substrate toform a cobalt-containing material thereon. In one example, a reactantplasma (e.g., hydrogen) is used to form a metallic cobalt material.However, a variety of reactants may be used to form cobalt-containingmaterials having a wide range of compositions. In one example, aboron-containing reactant compound (e.g., diborane) is used to form acobalt-containing material containing boride. In a preferred example, asilicon precursor (e.g., silane or disilane) is used to form a cobaltsilicide material.

The process chamber was exposed to a second purge step to remove excessprecursors or contaminants from the previous step. The flow rate of thereagent gas may be maintained or adjusted from the previous step duringthe purge step. An optional purge gas may be administered into theprocess chamber with a flow rate within a range from about 100 sccm toabout 2,000 sccm, preferably, from about 200 sccm to about 1,000 sccm,and more preferably, from about 300 sccm to about 700 sccm, for example,about 500 sccm. The second purge step may be conducted for a time periodwithin a range from about 0.1 seconds to about 8 seconds, preferably,from about 1 second to about 5 seconds, and more preferably, from about2 seconds to about 4 seconds.

The ALD cycle may be repeated until a predetermined thickness of thecobalt-containing material is deposited on the substrate. In oneexample, a cobalt silicide layer has a thickness of about 5 Å and ametallic cobalt layer has a thickness of about 10 Å. In another example,a cobalt silicide layer has a thickness of about 30 Å and a metalliccobalt layer has a thickness of about 50 Å. The processes as describedherein may deposit a cobalt-containing material at a rate of at least0.15 Å/cycle, preferably, at least 0.25 Å/cycle, more preferably, atleast 0.35 Å/cycle or faster. In another embodiment, the processes asdescribed herein overcome shortcomings of the prior art relative asrelated to nucleation delay. There is no detectable nucleation delayduring many, if not most, of the experiments to deposit thecobalt-containing materials.

In another embodiment, a cobalt-containing material may be formed duringanother PE-ALD process that provides sequentially exposing the substrateto pulses of a cobalt precursor and an active reagent, such as a reagentplasma. The substrate may be exposed to a cobalt precursor gas formed bypassing a carrier gas through an ampoule containing a cobalt precursor,as described herein. The cobalt precursor gas usually has a flow ratewithin a range from about 100 sccm to about 2,000 sccm, preferably, fromabout 200 sccm to about 1,000 sccm, and more preferably, from about 300sccm to about 700 sccm, for example, about 500 sccm. The substrate maybe exposed to the deposition gas containing the cobalt precursor and thereagent gas for a time period within a range from about 0.1 seconds toabout 8 seconds, preferably, from about 1 second to about 5 seconds, andmore preferably from about 2 seconds to about 4 seconds. The flow of thecobalt precursor gas may be stopped once the cobalt precursor isadsorbed on the substrate. The cobalt precursor may be a discontinuouslayer, continuous layer or even multiple layers.

Subsequently, the substrate and chamber are exposed to a purge step. Apurge gas may be administered into the process chamber during the purgestep. In one aspect, the purge gas is the reagent gas, such as ammonia,nitrogen or hydrogen. In another aspect, the purge gas may be adifferent gas than the reagent gas. For example, the reagent gas may beammonia and the purge gas may be nitrogen, hydrogen or argon. The purgegas may have a flow rate within a range from about 100 sccm to about2,000 sccm, preferably, from about 200 sccm to about 1,000 sccm, andmore preferably, from about 300 sccm to about 700 sccm, for example,about 500 sccm. The purge step removes any excess cobalt precursor andother contaminants within the process chamber. The purge step may beconducted for a time period within a range from about 0.1 seconds toabout 8 seconds, preferably, from about 1 second to about 5 seconds, andmore preferably, from about 2 seconds to about 4 seconds. A carrier gas,a purge gas and a process gas may contain nitrogen, hydrogen, argon,neon, helium, or combinations thereof.

The substrate and the adsorbed cobalt precursor thereon may be exposedto the reagent gas during the next step of the ALD process. Optionally,a carrier gas may be administered at the same time as the reagent gasinto the process chamber. The reagent gas may be ignited to form aplasma. The reagent gas usually has a flow rate within a range fromabout 100 sccm to about 3,000 sccm, preferably, from about 200 sccm toabout 2,000 sccm, and more preferably, from about 500 sccm to about1,500 sccm. In one example, silane is used as a reagent gas with a flowrate of about 1,500 sccm. The substrate may be exposed to the plasma fora time period within a range from about 0.1 seconds to about 20 seconds,preferably, from about 1 second to about 10 seconds, and morepreferably, from about 2 seconds to about 8 seconds. Thereafter, theplasma power may be turned off. In one example, the reagent may besilane, disilane, nitrogen, hydrogen, or combinations thereof, while theplasma may be a silane plasma, a nitrogen plasma, a hydrogen plasma, orcombinations thereof. The reactant plasma reacts with the adsorbedcobalt precursor on the substrate to form a cobalt-containing materialthereon. Preferably, the reactant plasma is used to form cobalt silicideand metallic cobalt materials. However, a variety of reactants may beused to form cobalt-containing materials having a wide range ofcompositions, as described herein.

The process chamber may be exposed to a second purge step to removeexcess precursors or contaminants from the process chamber. The flow ofthe reagent gas may have been stopped at the end of the previous stepand started during the purge step, if the reagent gas is used as a purgegas. Alternative, a purge gas that is different than the reagent gas maybe administered into the process chamber. The reagent gas or purge gasmay have a flow rate within a range from about 100 sccm to about 2,000sccm, preferably, from about 200 sccm to about 1,000 sccm, and morepreferably, from about 300 sccm to about 700 sccm, for example, about500 sccm. The second purge step may be conducted for a time periodwithin a range from about 0.1 seconds to about 8 seconds, preferably,from about 1 second to about 5 seconds, and more preferably, from about2 seconds to about 4 seconds.

The ALD cycle may be repeated until a predetermined thickness of thecobalt-containing material is deposited on the substrate. Thecobalt-containing material may be deposited with a thickness less than1,000 Å, preferably less than 500 Å and more preferably from about 10 Åto about 100 Å, for example, about 30 Å. The processes as describedherein may deposit a cobalt-containing material at a rate of at least0.15 Å/cycle, preferably, at least 0.25 Å/cycle, more preferably, atleast 0.35 Å/cycle or faster. In another embodiment, the processes asdescribed herein overcome shortcomings of the prior art relative asrelated to nucleation delay. There is no detectable nucleation delayduring many, if not most, of the experiments to deposit thecobalt-containing materials.

An important precursor characteristic is to have a favorable vaporpressure. Deposition precursors may have gas, liquid or solid states atambient temperature and pressure. However, within the CVD or ALDchamber, precursors are usually volatilized as gas or plasma. Precursorsare usually heated prior to delivery into the process chamber. Althoughmany variables affect the deposition rate during a CVD process or an ALDprocess to form cobalt-containing material, the size of the ligand on acobalt precursor is an important consideration in order to achieve apredetermined deposition rate. The size of the ligand does contribute todetermining the specific temperature and pressure required to vaporizethe cobalt precursor. Furthermore, a cobalt precursor has a particularligand steric hindrance proportional to the size of the ligands. Ingeneral, larger ligands provide more steric hindrance. Therefore, lessmolecules of a precursor more bulky ligands may be adsorbed on a surfaceduring the half reaction while exposing the substrate to the precursorthan if the precursor contained less bulky ligands. The steric hindranceeffect limits the amount of adsorbed precursors on the surface.Therefore, a monolayer of a cobalt precursor may be formed to contain amore molecularly concentrated by decreasing the steric hindrance of theligand(s). The overall deposition rate is proportionally related to theamount of adsorbed precursor on the surface, since an increaseddeposition rate is usually achieved by having more of the precursoradsorbed to the surface. Ligands that contain smaller functional groups(e.g., hydrogen or methyl) generally provide less steric hindrance thanligands that contain larger functional groups (e.g., aryl). Also, theposition on the ligand motif may affect the steric hindrance of theprecursor.

In some embodiments, the cobalt precursor and the reagent may besequentially introduced into the process chamber during a thermal ALDprocess or a PE-ALD process. Alternatively, in other embodiments, thecobalt precursor and the reagent may be simultaneously introduced intothe process chamber during a thermal CVD process, pulsed CVD process, aPE-CVD process, or a pulsed PE-CVD process. In other embodiments, thecobalt precursor may be introduced into the process chamber without areagent and during a thermal CVD process, pulsed CVD process, a PE-CVDprocess, or a pulsed PE-CVD process.

In other embodiments, the substrate may be exposed to a deposition gascontaining at least a cobalt precursor gas and a silicon precursor toform a cobalt silicide material during a CVD process, a PE-CVD process,or a pulsed PE-CVD process. The substrate may be exposed to a cobaltprecursor gas formed by passing a carrier gas (e.g., nitrogen or argon)through an ampoule of a cobalt precursor. Similar, a silicon precursorgas may be formed by passing a carrier gas through an ampoule of asilicon precursor. The ampoule may be heated depending on the cobalt andsilicon precursors used during the process. In one example, an ampoulecontaining a cobalt carbonyl compound (e.g., (CO)_(x)Co_(y)L_(z)) or anamido cobalt compound (e.g., (R₂N)_(x)Co) may be heated to a temperaturewithin a range from about 30° C. to about 500° C. The cobalt precursorgas usually has a flow rate within a range from about 100 sccm to about2,000 sccm, preferably, from about 200 sccm to about 1,000 sccm, andmore preferably, from about 300 sccm to about 700 sccm, for example,about 500 sccm. The cobalt precursor gas and the silicon precursor gasare combined to form a deposition gas. The silicon precursor gas (e.g.,SiH₄ or Si₂H₆) usually has a flow rate within a range from about 100sccm to about 3,000 sccm, preferably, from about 200 sccm to about 2,000sccm, and more preferably, from about 500 sccm to about 1,500 sccm. Inone example, silane is used as a silicon precursor with a flow rate ofabout 1,500 sccm. In another example, disilane is used as a siliconprecursor with a flow rate of about 1,200 sccm. The substrate may beexposed to the deposition gas containing the cobalt precursor gas andthe silicon precursor gas for a time period within a range from about0.1 seconds to about 120 seconds, preferably, from about 1 second toabout 60 seconds, and more preferably, from about 5 seconds to about 30seconds.

The process may be plasma-enhanced by igniting a plasma during thedeposition process. The plasma source may be an in situ plasma sourcewithin the CVD chamber or a RPS positioned outside of the CVD chamber.The process gas containing the cobalt precursor gas and the siliconprecursor gas may be pulsed sequentially with or without a purge gasinto the CVD chamber during a pulsed CVD process. In one example, thesubstrate is heated to a predetermined temperature and the precursorsreact to form a cobalt silicide material during a thermal CVD process.In another example, a plasma may remain ignited while the process gas ispulsed into the process chamber and the substrate is exposed to pulsesof the process gas. Alternatively, in another example, the ignition ofthe plasma may be pulsed while the process gas maintains a steady gasinto the process chamber and the substrate is exposed to the flow of theprocess gas.

In other embodiments, the substrate may be simultaneously exposed to acobalt precursor gas and a reducing agent to form a metallic cobaltmaterial during a CVD process, a PE-CVD process, or a pulsed PE-CVDprocess. The substrate may be exposed to a cobalt precursor gas formedby passing a carrier gas (e.g., nitrogen or argon) through an ampoule ofa cobalt precursor. Similar, a reducing agent gas may be formed bypassing a carrier gas through an ampoule of a reducing agent. Theampoule may be heated depending on the cobalt and reducing agents usedduring the process. In one example, an ampoule containing a cobaltcarbonyl compound (e.g., (CO)_(x)Co_(y)L_(z)) or an amido cobaltcompound (e.g., (R₂N)_(x)Co) may be heated to a temperature within arange from about 30° C. to about 500° C. The cobalt precursor gasusually has a flow rate within a range from about 100 sccm to about2,000 sccm, preferably, from about 200 sccm to about 1,000 sccm, andmore preferably, from about 300 sccm to about 700 sccm, for example,about 500 sccm. The cobalt precursor gas and the reducing agent gas arecombined to form a deposition gas. The reducing agent gas usually has aflow rate within a range from about 100 sccm to about 3,000 sccm,preferably, from about 200 sccm to about 2,000 sccm, and morepreferably, from about 500 sccm to about 1,500 sccm. In one example,hydrogen is used as a reducing agent with a flow rate of about 2,000sccm. In another example, diborane is used as a reducing agent with aflow rate of about 800 sccm. The substrate may be exposed to thedeposition gas containing the cobalt precursor gas and the reducingagent gas for a time period within a range from about 0.1 seconds toabout 120 seconds, preferably, from about 1 second to about 60 seconds,and more preferably, from about 5 seconds to about 30 seconds.

The process may be plasma-enhanced by igniting a plasma during thedeposition process. The plasma source may be an in situ plasma sourcewithin the CVD chamber or a RPS positioned outside of the CVD chamber.The process gas containing the cobalt precursor gas and the reducingagent gas may be pulsed sequentially with or without a purge gas intothe CVD chamber during a pulsed CVD process. In one example, thesubstrate is heated to a predetermined temperature and the precursorsreact to form a metallic cobalt material during a thermal CVD process.In another example, a plasma may remain ignited while the process gas ispulsed into the process chamber and the substrate is exposed to pulsesof the process gas. Alternatively, in another example, the ignition ofthe plasma may be pulsed while the process gas maintains a steady gasinto the process chamber and the substrate is exposed to the flow of theprocess gas.

In another embodiment, a cobalt silicide material is deposited on asilicon-containing substrate surface during a vapor deposition processand a metallic cobalt material is deposited thereon by another vapordeposition process. Preferably, the cobalt silicide material and themetallic cobalt material are deposited within the same CVD chamber. Inone aspect, the cobalt silicide layer is deposited by co-flowing acobalt precursor and a silicon precursor during a CVD process.Thereafter, the flow of silicon precursor into the CVD chamber isstopped while the flow of the cobalt precursor is continued and ametallic cobalt material is deposited on the cobalt silicide material. Areductant, such as hydrogen, may be co-flowed with the cobalt precursor.Alternatively, the cobalt precursor may be reduced by a thermaldecomposition process or a plasma process during the CVD process.

Suitable cobalt precursors for forming cobalt-containing materials(e.g., cobalt silicide or metallic cobalt) by deposition processes(e.g., CVD or ALD) described herein include cobalt carbonyl complexes,cobalt amidinates compounds, cobaltocene compounds, cobalt dienylcomplexes, cobalt nitrosyl complexes, derivatives thereof, complexesthereof, plasma thereof, or combinations thereof.

In one embodiment, cobalt carbonyl complexes may be a preferred cobaltprecursor. Cobalt carbonyl complexes have the general chemical formula(CO)_(x)Co_(y)L_(z), where X may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,or 12, Y may be 1, 2, 3, 4, or 5, and Z may be 1, 2, 3, 4, 5, 6, 7, or8. The group L is absent, one ligand or multiple ligands, that may bethe same ligand or different ligands, and include cyclopentadienyl,alkylcyclopentadienyl (e.g., methylcyclopentadienyl orpentamethylcyclopentadienyl), pentadienyl, alkylpentadienyl,cyclobutadienyl, butadienyl, ethylene, allyl (or propylene), alkenes,dialkenes, alkynes, acetylene, bytylacetylene, nitrosyl, ammonia,derivatives thereof, complexes thereof, plasma thereof, or combinationsthereof. Some exemplary cobalt carbonyl complexes includecyclopentadienyl cobalt bis(carbonyl) (CpCo(CO)₂), tricarbonyl allylcobalt ((CO)₃Co(CH₂CH═CH₂)), dicobalt hexacarbonyl bytylacetylene(CCTBA, (CO)₆Co₂(HC≡C^(t)Bu)), dicobalt hexacarbonylmethylbytylacetylene ((CO)₆Co₂(MeC≡C^(t)Bu)), dicobalt hexacarbonylphenylacetylene ((CO)₆Co₂(HC≡CPh)), hexacarbonyl methylphenylacetylene((CO)₆Co₂(MeC≡CPh)), dicobalt hexacarbonyl methylacetylene((CO)₆Co₂(HC≡CMe)), dicobalt hexacarbonyl dimethylacetylene((CO)₆Co₂(MeC≡CMe)), derivatives thereof, complexes thereof, plasmathereof, or combinations thereof.

In another embodiment, cobalt amidinates or cobalt amido complexes maybe a preferred cobalt precursor. Cobalt amido complexes have the generalchemical formula (RR′N)_(x)Co, where X may be 1, 2, or 3, and R and R′are independently hydrogen, methyl, ethyl, propyl, butyl, alkyl, silyl,alkylsilyl, derivatives thereof, or combinations thereof. Some exemplarycobalt amido complexes include bis(di(butyldimethylsilyl)amido) cobalt(((BuMe₂Si)₂N)₂Co), bis(di(ethyldimethylsilyl)amido) cobalt(((EtMe₂Si)₂N)₂Co), bis(di(propyldimethylsilyl)amido) cobalt(((PrMe₂Si)₂N)₂Co), bis(di(trimethylsilyl)amido) cobalt(((Me₃Si)₂N)₂Co), tris(di(trimethylsilyl)amido) cobalt (((Me₃Si)₂N)₃Co),derivatives thereof, complexes thereof, plasma thereof, or combinationsthereof.

Other exemplary cobalt precursors include methylcyclopentadienyl cobaltbis(carbonyl) (MeCpCo(CO)₂), ethylcyclopentadienyl cobalt bis(carbonyl)(EtCpCo(CO)₂), pentamethylcyclopentadienyl cobalt bis(carbonyl)(Me₅CpCo(CO)₂), dicobalt octa(carbonyl) (Co₂(CO)₅), nitrosyl cobalttris(carbonyl) ((ON)Co(CO)₃), bis(cyclopentadienyl)cobalt,(cyclopentadienyl)cobalt (cyclohexadienyl), cyclopentadienyl cobalt(1,3-hexadienyl), (cyclobutadienyl)cobalt (cyclopentadienyl),bis(methylcyclopentadienyl)cobalt, (cyclopentadienyl)cobalt(5-methylcyclopentadienyl), bis(ethylene)cobalt(pentamethylcyclopentadienyl), cobalt tetracarbonyl iodide, cobalttetracarbonyl trichlorosilane, carbonyl chloridetris(trimethylphosphine) cobalt, cobalttricarbonyl-hydrotributylphosphine, acetylene dicobalt hexacarbonyl,acetylene dicobalt pentacarbonyl triethylphosphine, derivatives thereof,complexes thereof, plasma thereof, or combinations thereof.

Suitable silicon precursors for forming cobalt-containing materials(e.g., cobalt silicide) by deposition processes (e.g., CVD or ALD)described herein include silane (SiH₄), disilane (Si₂H₆), trisilane(Si₃H₈), tetrasilane (Si₄H₁₀), dimethylsilane (SiC₂H₈), methyl silane(SiCH₆), ethylsilane (SiC₂H₈), chlorosilane (ClSiH₃), dichlorosilane(Cl₂SiH₂), tetrachlorosilane (Cl₄Si), hexachlorodisilane (Si₂Cl₆),plasmas thereof, derivatives thereof, or combinations thereof.

Other suitable reagents, including reductants, that are useful to formcobalt-containing materials (e.g., cobalt silicide or metallic cobalt)by processes described herein include hydrogen (e.g., H₂ or atomic-H),atomic-N, ammonia (NH₃), hydrazine (N₂H₄), borane (BH₃), diborane(B₂H₆), triborane, tetraborane, pentaborane, triethylborane (Et₃B),phosphine (PH₃), derivatives thereof, plasmas thereof, or combinationsthereof.

The time interval for the pulse of the cobalt precursor is variabledepending upon a number of factors such as, for example, the volumecapacity of the process chamber employed, the vacuum system coupledthereto and the volatility/reactivity of the reactants used during theALD process. For example, (1) a large-volume process chamber may lead toa longer time to stabilize the process conditions such as, for example,carrier/purge gas flow and temperature, requiring a longer pulse time;(2) a lower flow rate for the process gas may also lead to a longer timeto stabilize the process conditions requiring a longer pulse time; and(3) a lower chamber pressure means that the process gas is evacuatedfrom the process chamber more quickly requiring a longer pulse time. Ingeneral, the process conditions are advantageously selected so that apulse of the cobalt precursor provides a sufficient amount of precursorso that at least a monolayer of the cobalt precursor is adsorbed on thesubstrate. Thereafter, excess cobalt precursor remaining in the chambermay be removed from the process chamber by the constant carrier gasstream in combination with the vacuum system.

The time interval for each of the pulses of the cobalt precursor and thereagent gas may have the same duration. That is, the duration of thepulse of the cobalt precursor may be identical to the duration of thepulse of the reagent gas. For such an embodiment, a time interval (T₁)for the pulse of the cobalt precursor is equal to a time interval (T₂)for the pulse of the reagent gas.

Alternatively, the time interval for each of the pulses of the cobaltprecursor and the reagent gas may have different durations. That is, theduration of the pulse of the cobalt precursor may be shorter or longerthan the duration of the pulse of the reagent gas. For such anembodiment, a time interval (T₁) for the pulse of the cobalt precursoris different than the time interval (T₂) for the pulse of the reagentgas.

In addition, the periods of non-pulsing between each of the pulses ofthe cobalt precursor and the reagent gas may have the same duration.That is, the duration of the period of non-pulsing between each pulse ofthe cobalt precursor and each pulse of the reagent gas is identical. Forsuch an embodiment, a time interval (T₃) of non-pulsing between thepulse of the cobalt precursor and the pulse of the reagent gas is equalto a time interval (T₄) of non-pulsing between the pulse of the reagentgas and the pulse of the cobalt precursor. During the time periods ofnon-pulsing only the constant carrier gas stream is provided to theprocess chamber.

Alternatively, the periods of non-pulsing between each of the pulses ofthe cobalt precursor and the reagent gas may have different duration.That is, the duration of the period of non-pulsing between each pulse ofthe cobalt precursor and each pulse of the reagent gas may be shorter orlonger than the duration of the period of non-pulsing between each pulseof the reagent gas and the cobalt precursor. For such an embodiment, atime interval (T₃) of non-pulsing between the pulse of the cobaltprecursor and the pulse of the reagent gas is different from a timeinterval (T₄) of non-pulsing between the pulse of the reagent gas andthe pulse of cobalt precursor. During the time periods of non-pulsingonly the constant carrier gas stream is provided to the process chamber.

Additionally, the time intervals for each pulse of the cobalt precursor,the reagent gas and the periods of non-pulsing therebetween for eachdeposition cycle may have the same duration. For such an embodiment, atime interval (T₁) for the cobalt precursor, a time interval (T₂) forthe reagent gas, a time interval (T₃) of non-pulsing between the pulseof the cobalt precursor and the pulse of the reagent gas and a timeinterval (T₄) of non-pulsing between the pulse of the reagent gas andthe pulse of the cobalt precursor each have the same value for eachdeposition cycle. For example, in a first deposition cycle (C₁), a timeinterval (T₁) for the pulse of the cobalt precursor has the sameduration as the time interval (T₁) for the pulse of the cobalt precursorin subsequent deposition cycles (C₂ . . . C_(n)). Similarly, theduration of each pulse of the reagent gas and the periods of non-pulsingbetween the pulse of the cobalt precursor and the reagent gas in thefirst deposition cycle (C₁) is the same as the duration of each pulse ofthe reagent gas and the periods of non-pulsing between the pulse of thecobalt precursor and the reagent gas in subsequent deposition cycles (C₂. . . C_(n)), respectively.

Alternatively, the time intervals for at least one pulse of the cobaltprecursor, the reagent gas and the periods of non-pulsing therebetweenfor one or more of the deposition cycles of the cobalt-containingmaterial deposition process may have different durations. For such anembodiment, one or more of the time intervals (T₁) for the pulses of thecobalt precursor, the time intervals (T₂) for the pulses of the reagentgas, the time intervals (T₃) of non-pulsing between the pulse of thecobalt precursor and the reagent gas and the time intervals (T₄) ofnon-pulsing between the pulses of the reagent gas and the cobaltprecursor may have different values for one or more deposition cycles ofthe cyclical deposition process. For example, in a first depositioncycle (C₁), the time interval (T₁) for the pulse of the cobalt precursormay be longer or shorter than one or more time interval (T₁) for thepulse of the cobalt precursor in subsequent deposition cycles (C₂ . . .C_(n)). Similarly, the durations of the pulses of the reagent gas andthe periods of non-pulsing between the pulse of the cobalt precursor andthe reagent gas in the first deposition cycle (C₁) may be the same ordifferent than the duration of each pulse of the reagent gas and theperiods of non-pulsing between the pulse of the cobalt precursor and thereagent gas in subsequent deposition cycles (C₂ . . . C_(n)).

In some embodiments, a constant flow of a carrier gas or a purge gas maybe provided to the process chamber modulated by alternating periods ofpulsing and non-pulsing where the periods of pulsing alternate betweenthe cobalt precursor and the reagent gas along with the carrier/purgegas stream, while the periods of non-pulsing include only thecarrier/purge gas stream.

Cobalt-containing Materials by Cyclic Process Using CVD or ALD

In other embodiments, cobalt-containing materials may be formed by acyclic process that sequentially exposes a substrate to a depositionprocess and a plasma treatment process. A soak process and purge stepsmay also be included in cyclic process. In one embodiment, a singlecycle of the cyclic process may include exposing the substrate to adeposition gas, purging the process chamber, exposing the substrate to aplasma treatment, optionally purging the process chamber, exposing thesubstrate to a soak process, and purging the process chamber. In anotherembodiment, a single cycle of the cyclic process may include exposingthe substrate to a deposition gas, purging the process chamber, exposingthe substrate to a plasma treatment, and purging the process chamber.The cycle process may be stopped after one cycle, but usually isconducted multiple times until a predetermined thickness of thecobalt-containing material is deposited on the substrate.

FIG. 20 depicts a flow chart of process 2000 which may be used to formcobalt-containing materials, such as a cobalt silicide material. In oneembodiment, process 2000 includes exposing a substrate to a depositiongas to form a cobalt silicide material (step 2010), purging thedeposition chamber (step 2020), exposing the substrate to a plasmatreatment process (step 2030), optionally purging the deposition chamber(step 2040), exposing the substrate to a soak process (step 2050),purging the deposition chamber (step 2060), and determining if apredetermined thickness of the cobalt silicide material has been formedon the substrate (step 2070). The cycle of steps 2010-2070 may berepeated if the cobalt silicide material has not been formed having thepredetermined thickness. Alternately, process 2000 may be stopped oncethe cobalt silicide material has been formed having the predeterminedthickness.

FIG. 21 depicts a flow chart of process 2100 which may be used to formcobalt-containing materials, such as a metallic cobalt material. In oneembodiment, process 2100 includes exposing a substrate to a depositiongas to form a metallic cobalt material (step 2110), purging thedeposition chamber (step 2120), exposing the substrate to a plasmatreatment process (step 2130), purging the deposition chamber (step2140), and determining if a predetermined thickness of the metalliccobalt material has been formed on the substrate (step 2150). The cycleof steps 2110-2150 may be repeated if the metallic cobalt material hasnot been formed having the predetermined thickness. Alternately, process2100 may be stopped once the metallic cobalt material has been formedhaving the predetermined thickness.

FIG. 22 depicts a flow chart of process 2200 which may be used to formcobalt-containing materials, such as a cobalt silicide material. In oneembodiment, process 2200 includes optionally exposing a substrate to apre-treatment process (2210), exposing a substrate to asilicon-containing reducing gas (step 2220), exposing the substrate to ahydrogen plasma and the silicon-containing reducing gas (step 2230),exposing the substrate to the silicon-containing reducing gas withoutthe plasma (step 2240), exposing the substrate to a cobalt precursor andthe silicon-containing reducing gas (step 2250), and determining if apredetermined thickness of the cobalt silicide material has been formedon the substrate (step 2260). The cycle of steps 2210-2260 may berepeated if the cobalt silicide material has not been formed having thepredetermined thickness. Alternately, process 2200 may be stopped oncethe cobalt silicide material has been formed having the predeterminedthickness. In one embodiment, the substrate may be optionally exposed toa post-treatment, such as a thermal annealing process or a plasmaprocess, during step 2270.

In one embodiment of process 2200, the silicon-containing reducing gasmay be continuously flowed into the process chamber while the hydrogenplasma and the cobalt precursor are sequentially pulsed into the processchamber. In one example, FIG. 23 shows a graph of the timing sequencesfor various chemical species or chemical precursors during a cobaltsilicide deposition process, such as process 2200. Thesilicon-containing reducing gas, which contains a silicon precursor andmay contain a carrier gas (e.g., H₂ or Ar), is shown to remain on duringthe time period from the initial time (t₀) of the deposition cycle tothe final time (t₄) of the first deposition cycle and to the final time(t₈) of the second deposition cycle. The silicon-containing reducing gasmay be used as a purge gas as well as a soak gas. While the substrate isexposed to the silicon-containing reducing gas, a hydrogen plasma and acobalt precursor are sequentially pulsed into the process chamber andexposed to the substrate. For example, the substrate is exposed to onlythe silicon-containing reducing gas between t₀-t₁, t₂-t₃, t₄-t₈, andt₆-t₇, exposed to a hydrogen plasma between t₁-t₂ and t₅-t₆, and exposedto a cobalt precursor between t₃-t₄ and t₇-t₈.

The substrate may be exposed to the silicon-containing reducing gasduring the time ranges of t₀-t₁, t₂-t₃, t₄-t₅, or t₆-t₇, where each ofthe time ranges may last for a time period within a range from about 0.5seconds to about 10 seconds, preferably, from about 1 second to about 5seconds, and more preferably, from about 2 seconds to about 4 seconds.The substrate may be exposed to the hydrogen plasma during the timeranges of t₁-t₂ or t₅-t₆, where each of the time ranges may last for atime period within a range from about 0.5 seconds to about 10 seconds,preferably, from about 1 second to about 5 seconds, and more preferably,from about 2 seconds to about 3 seconds. The substrate may be exposed tothe cobalt precursor during the time ranges of between t₃-t₄ and t₇-t₈,where each of the time ranges may last for a time period within a rangefrom about 0.5 seconds to about 10 seconds, preferably, from about 1second to about 5 seconds, and more preferably, from about 2 seconds toabout 3 seconds.

In one embodiment, a method for forming a cobalt-containing material ona substrate is provided which includes heating a substrate to apredetermined temperature within a processing chamber, forming a cobaltsilicide material on the substrate by conducting a deposition cycle todeposit a cobalt silicide layer, and repeating the deposition cycle toform a plurality of the cobalt silicide layers. In one aspect, thedeposition cycle includes exposing the substrate to a silicon-containingreducing gas while sequentially exposing the substrate to a cobaltprecursor and a plasma. In another aspect, the deposition cycle includesexposing the substrate to a gas flow comprising a silicon-containingreducing gas, and exposing the substrate sequentially to a cobaltprecursor and a plasma, wherein the cobalt precursor is added into thegas flow comprising the silicon-containing reducing gas whilealternately igniting the plasma. In another aspect, the deposition cycleincludes exposing the substrate to a silicon-containing reducing gas,igniting a plasma and exposing the substrate to the plasma and thesilicon-containing reducing gas, extinguishing the plasma and exposingthe substrate to the silicon-containing reducing gas, exposing thesubstrate to a cobalt precursor and the silicon-containing reducing gasand ceasing the exposure of the cobalt precursor and exposing thesubstrate to a silicon-containing reducing gas.

For example, the substrate may be exposed to the silicon-containingreducing gas and the cobalt precursor during a first time period (t₃-t₄or t₇-t₈) within a range from about 1 second to about 10 seconds,preferably, from about 2 seconds to about 5 seconds. The substrate maybe exposed to the silicon-containing reducing gas and the plasma duringa second time period (t₁-t₂ or t₅-t₆) within a range from about 1 secondto about 10 seconds, preferably, from about 2 seconds to about 5seconds. The substrate may be exposed to the silicon-containing reducinggas after the cobalt precursor exposure and prior to the plasma exposureduring a third time period (t₀-t₁ or t₄-t₅) within a range from about 1second to about 10 seconds, preferably, from about 2 seconds to about 4seconds. Also, the substrate may be exposed to the silicon-containingreducing gas after the plasma exposure and prior to the cobalt precursorexposure during a fourth time period (t₂-t₃ or t₆-t₇) within a rangefrom about 1 second to about 10 seconds, preferably, from about 2seconds to about 4 seconds.

FIGS. 25A-25B depict schematic cross-sectional views of substrate 2500during different stages of a cobalt silicide deposition process, asdescribed by embodiments herein. Substrate 2500 contains multiplecobalt-silicon layers 2520 and silyl layers 2530 alternately stackedover surface 2510 (FIG. 25A). Surface 2510 may be the surface of avariety of different materials, including dielectric materials, barriermaterials, conductive materials, but preferably is a silicon-containingsurface, such as a substrate surface. Subsequent a thermal annealingprocess, cobalt silicide layers 2520 and silyl layers 2530 aretransformed into cobalt silicide material 2540 formed on substrate 2500(FIG. 25B).

The alternately stacked layers of cobalt silicide layers 2520 and silyllayers 2530 may be formed by an ALD process or a CVD process asdescribed herein. Cobalt silicide layers 2520 may be formed by exposingthe substrate sequentially to a cobalt precursor and a silicon precursorduring an ALD process or a PE-ALD process. Alternately, cobalt silicidelayers 2520 may be formed by exposing the substrate simultaneously to acobalt precursor and a silicon precursor during a CVD process or aPE-CVD process.

In one embodiment, cobalt silicide layers 2520 may contain asilicon/cobalt atomic ratio of greater than about 0.5, preferably,greater than about 1, and more preferably, within a range from about 1to about 2. Therefore, cobalt silicide layers 2520 may contain cobaltsilicide having the chemical formula of CoSi_(x), wherein X may bewithin a range from about 0.5 to about 2, preferably, from about 1 toabout 2. However, in another embodiment, cobalt silicide layers 2520contains a silicon/cobalt atomic ratio of about 1 or less, such aswithin a range from about 0.1 to about 1, preferably, from about 0.5 toabout 1. Therefore, cobalt silicide layers 2520 may contain cobaltsilicide having the chemical formula of CoSi_(x), wherein X may bewithin a range from about 0.1 to about 1, preferably, from about 0.5 toabout 1.

It is believed that due to the thermodynamic properties of cobaltsilicide, a silicon/cobalt atomic ratio of about 1 or less is favoreduntil the cobalt silicide is heated to a predetermined temperature andtime and is exposed to an available silicon source. Thereafter, asilicon/cobalt atomic ratio of greater than about 1, such as up to about2, is obtained for the cobalt silicide material.

Silyl layers 2530 may be formed prior to, during, or subsequent to anALD process or a CVD process. Silyl layer 2530 may be formed by exposingthe substrate to a silicon-containing reducing gas during a soak processor a treatment process. The silyl layers 2530 contain silicon hydrogenbonds.

Substrate 2500 may be exposed to a thermal annealing process, a plasmaprocess, or both while forming cobalt silicide material 2540. In oneembodiment, cobalt silicide material 2540 may be formed by exposingsubstrate 2500 to an annealing process, such as an RTP, at a temperatureof about 500° C. or greater, preferably, at about 550° C. or greater,such as within a range from about 650° C. to about 750° C. or greater.During the annealing process, the RTP chamber may contain nitrogen gas,argon, hydrogen, or combinations thereof. In another embodiment, cobaltsilicide material 2540 may be formed by exposing substrate 2500 to ahydrogen plasma for a time period of about 5 seconds or greater,preferably, for about 10 seconds or greater, and more preferably, forabout 20 seconds or greater. The plasma may have a power within a rangefrom about 800 watts to about 1,200 watts. In one example, substrate2500 is exposed to a hydrogen plasma having a power setting of about1,000 watts for about 20 seconds. The hydrogen plasma contains hydrogengas (H₂) and may also contain nitrogen gas (N₂), argon, or mixturesthereof.

In one embodiment, cobalt silicide material 2540 may contain asilicon/cobalt atomic ratio of greater than about 0.5, preferably,greater than about 1, and more preferably, within a range from about 1to about 2. Therefore, cobalt silicide material 2540 may contain cobaltsilicide having the chemical formula of CoSi_(x), wherein X may bewithin a range from about 0.5 to about 2, preferably, from about 1 toabout 2.

One advantage realized by several of the processes described herein,including process 2200, is a reduction of silicon erosion fromsilicon-containing materials, such as the substrate or other siliconsurfaces. Silicon erosion, especially from the substrate, can causejunction leakage and ultimately device failure due to the formed voidswithin the silicon-containing material. In some embodiments, cobaltsilicide layers 2520 may have the chemical formula of CoSi_(x), whereinX may be within a range from about 0.1 to about 1. Due to theavailability of the silicon source between each of cobalt silicidelayers 2520, namely silyl layers 2530, during the formation of cobaltsilicide material 2540, silicon atoms are consumed from silyl layers2530 instead of a silicon surface, such as surface 2510. Therefore, asilicon-rich cobalt silicide material 2530 (e.g., CoSi_(x), wherein Xmay be within a range from about 1 to about 2) may be formed while verylittle or no silicon is pulled from surface 2510.

The thickness for the cobalt-containing material is variable dependingon the device structure to be fabricated. The cobalt-containing materialmay be formed on the substrate until a predetermined thickness isachieved per steps 2070, 2150, and 2260. The cyclic process may form ordeposit a cobalt-containing material on the substrate at a rate within arange from about 2 Å/cycle to about 50 Å/cycle, preferably, from about 3Å/cycle to about 30 Å/cycle, more preferably, from about 5 Å/cycle toabout 20 Å/cycle, for example, about 8 Å/cycle. In one embodiment, thethickness of the cobalt silicide material is less than about 300 Å,preferably, within a range from about 5 Å to about 200 Å, morepreferably, from about 10 Å to about 100 Å, more preferably, from about15 Å to about 50 Å, and more preferably, from about 25 Å to about 30 Å.Metallic cobalt material may have a film thickness within a range fromabout 5 Å to about 300 Å, preferably, from about 10 Å to about 100 Å,more preferably, from about 20 Å to about 70 Å, and more preferably,from about 40 Å to about 50 Å, for example, about 45 Å.

Generally, the substrate may be exposed to the deposition gas for a timeperiod of about 1 second to about 60 seconds, preferably, from about 2seconds to about 20 seconds, more preferably, from about 3 seconds toabout 10 seconds, for example, about 5 seconds.

A plasma may be generated external from the process chamber, such as bya RPS system, or preferably, the plasma may be generated in situ aplasma capable deposition chamber, such as a PE-CVD chamber during aplasma treatment process, such as in steps 2030, 2130, 2230, 2410, 2430,2450, 2610, or 2630. The substrate may be exposed to the plasmatreatment process for a time period of about 5 seconds to about 120seconds, preferably, from about 10 seconds to about 90 seconds, morepreferably, from about 15 seconds to about 60 seconds, for example,about 30 seconds. The plasma may be generated from a microwave (MW)frequency generator or a radio frequency (RF) generator. In a preferredexample, an in situ plasma is generated by a RF generator. Thedeposition chamber may be pressurized during the plasma treatmentprocess at a pressure within a range from about 0.1 Torr to about 80Torr, preferably from about 0.5 Torr to about 10 Torr, and morepreferably, from about 1 Torr to about 5 Torr. Also, the chamber or thesubstrate may be heated to a temperature of less than about 500° C.,preferably within a range from about 100° C. to about 450° C., and morepreferably, from about 150° C. to about 400° C., for example, about 300°C.

During PE-ALD processes, a plasma may be ignited within the depositionchamber for an in situ plasma process, or alternative, may be formed byan external source, such as a RPS system. The RF generator may be set ata frequency within a range from about 100 kHz to about 60 MHz. In oneexample, a RF generator, with a frequency of 13.56 MHz, may be set tohave a power output within a range from about 100 watts to about 1,000watts, preferably, from about 250 watts to about 600 watts, and morepreferably, from about 300 watts to about 500 watts. In one example, aRF generator, with a frequency of 350 kHz, may be set to have a poweroutput within a range from about 200 watts to about 2,000 watts,preferably, from about 500 watts to about 1,500 watts, and morepreferably, from about 800 watts to about 1,200 watts, for example,about 1,000 watts. A surface of substrate may be exposed to a plasmahaving a power per surface area value within a range from about 0.01watts/cm² to about 10.0 watts/cm², preferably, from about 0.05 watts/cm²to about 6.0 watts/cm².

In one embodiment, the substrate may be exposed to a soak process gasduring a soak process (step 2050), a pre-treatment process (steps 2210or 2610), post-treatment process (step 2270), treatment processes (steps2410, 2430, or 2450). A soak process gas may contain at least onereducing gas and a carrier gas. In one example, a soak process gascontains at least one reducing gas, hydrogen gas (H₂), and a carriergas. In another example, the substrate may be exposed to a silicon soakprocess to form a thin silicon-containing layer on the cobalt-containingmaterial prior to ending process 2000. In one embodiment, a plasma maybe ignited while the substrate is being exposed to a soak process gas.The silicon soak process may be performed in situ within the samechamber as the cobalt-containing material deposition (step 2010). Thesubstrate may be exposed to the soak process for a time period of about1 second to about 60 seconds, preferably, from about 2 seconds to about30 seconds, more preferably, from about 3 seconds to about 20 seconds,for example, about 5 seconds. In one example, a substrate containingcobalt silicide is exposed to a hydrogen-plasma (e.g., H₂ or H₂/Ar) forabout 20 seconds.

Suitable silicon-reducing gases that may be exposed to the substrateduring a soak process (including pre- and post-soak), treatment process(including pre- and post-treatment), or deposition process as describedherein include silane (SiH₄), disilane (Si₂H₆), trisilane (Si₃H₈),tetrasilane (Si₄H₁₀), dimethylsilane (SiC₂H₈), methyl silane (SiCH₆),ethylsilane (SiC₂H₆), chlorosilane (ClSiH₃), dichlorosilane (Cl₂SiH₂),tetrachlorosilane (Cl₄Si), hexachlorodisilane (Si₂Cl₆), plasmas thereof,derivatives thereof, or combinations thereof. In one embodiment, silaneor disilane are preferably used as silicon-reducing gases during a soakprocess, treatment process, or deposition process. Other reducing gasesthat may be contained in a soak process gas and exposed to the substrateduring a soak process as described herein include hydrogen (e.g., H₂ oratomic-H), atomic-N, ammonia (NH₃), hydrazine (N₂H₄), borane (BH₃),diborane (B₂H₆), triborane, tetraborane, pentaborane, triethylborane(Et₃B), phosphine (PH₃), derivatives thereof, plasmas thereof, orcombinations thereof. A carrier gas may be combined with asilicon-reducing gas either in situ or ex situ the deposition chamber.The carrier gas may be hydrogen, argon, nitrogen, helium, or mixturesthereof.

A reducing gas, such as a silicon-reducing gas, may be introduced intothe deposition chamber having a flow rate within a range from about 500sccm to about 2,500 sccm, preferably, from about 700 sccm to about 2,000sccm, and more preferably, from about 800 sccm to about 1,500 sccm, forexample, about 1,000 sccm during the soak process. Hydrogen gas may beintroduced into the deposition chamber having a flow rate within a rangefrom about 500 sccm to about 5,000 sccm, preferably, from about 1,000sccm to about 4,000 sccm, and more preferably, from about 2,000 sccm toabout 3,500 sccm, for example, about 3,000 sccm during the soak process.A carrier gas, such as argon, nitrogen, or helium, may be introducedinto the deposition chamber having a flow rate within a range from about500 sccm to about 2,500 sccm, preferably, from about 700 sccm to about2,000 sccm, and more preferably, from about 800 sccm to about 1,500sccm, for example, about 1,000 sccm during the soak process. Thedeposition chamber may have a chamber pressure within a range from about100 milliTorr and about 300 Torr. The deposition chamber or thesubstrate may be heated to a temperature of less than about 500° C.,preferably within a range from about 100° C. to about 450° C., and morepreferably, from about 150° C. to about 400° C., for example, about 300°C. during the soak process.

The deposition chamber may be purged with and the substrate may beexposed to a purge gas or a carrier gas during a purge process prior toor subsequent to the deposition process, the plasma treatment process,or the soak process during optional purge steps 2020, 2040, 2060, 2120,and 2140. Any one of purge steps 2020, 2040, 2060, 2120, and 2140 may beincluded or excluded during processes 2000 and 2100. In an alternativeembodiment, deposition chamber may be purged with and the substrate maybe exposed to silicon-containing reducing gas (e.g., SiH₄ or Si₂H₆)during a purge process prior to or subsequent to the deposition process,the plasma treatment process, or the soak process during optional purgesteps 2220 and 2240. The purge gas or carrier gas may include argon,nitrogen, hydrogen, helium, forming gas, or combinations thereof. Thepurge gas introduced into the deposition chamber may contain one gas ora mixture of gases and may be introduced in a single step or in severalsteps. For example, the deposition chamber may be purged with a gasmixture of argon and hydrogen during a first time period and then purgedwith hydrogen during a second time period. Each step of the purgeprocess may last for a time period of about 0.1 seconds to about 30seconds, preferably, from about 0.5 seconds to about 10 seconds, morepreferably, from about 1 second to about 5 seconds, for example, about 2seconds. The purge gas or carrier gas may be introduced into thedeposition chamber having a flow rate within a range from about 500 sccmto about 5,000 sccm, preferably, from about 1,000 sccm to about 4,000sccm, and more preferably, from about 2,000 sccm to about 3,500 sccm,for example, about 3,000 sccm during the purge process. In one example,the deposition chamber may be purged with a gas mixture of argon havinga flow rate of about 500 sccm and hydrogen gas having a flow rate ofabout 3,000 sccm for about 2 seconds. Thereafter, the deposition chambermay be purged with hydrogen gas having a flow rate of about 3,000 sccmfor about 2 seconds.

In another embodiment, FIG. 24 depicts a flow chart of process 2400which includes optionally exposing a substrate to a treatment or apreclean process (step 2410), depositing a cobalt silicide material onthe substrate (step 2420), optionally exposing a substrate to atreatment (step 2430), depositing a metallic material on the substrate(step 2440), and optionally exposing a substrate to a treatment (step2450). The metallic material may contain at least one element of cobalt,nickel, platinum, palladium, rhodium, alloys thereof, or combinationsthereof, and may be formed or deposited in one or in multiple depositionprocesses including ALD, PE-ALD, CVD, PE-CVD, pulsed-CVD, PVD, ECP,electroless plating, or derivatives thereof. The metallic material maybe exposed to a silicon-containing reducing gas during a pre-soakprocess or a post-soak process. In some examples, the metallic materialmay be exposed to a plasma treatment during the pre-soak process or thepost-soak process.

In another embodiment, FIG. 26 depicts a flow chart of process 2600which includes exposing a substrate to a pre-treatment or a precleanprocess (step 2610), depositing a cobalt silicide material on thesubstrate (step 2620), exposing the substrate to an annealing process(step 2630), depositing at least one barrier material on the substrate(step 2640), depositing a metallic contact material on the substrate(step 2650), and exposing the substrate to etching process or aplanarization process. The barrier material may contain cobalt,tantalum, tantalum nitride, titanium, titanium nitride, tungsten,tungsten nitride, alloys thereof, or derivatives thereof. Also, thebarrier material may contain multiple layers of barrier layers oradhesion layers, such as Ti/TiN, Ta/TaN, or W/WN. The barrier materialmay be exposed to a silicon-containing reducing gas during a pre-soakprocess or a post-soak process. In some examples, the barrier materialmay be exposed to a plasma treatment during the pre-soak process or thepost-soak process.

In an alternative embodiment, a method for forming a metallic silicidecontaining material on a substrate is provided which includes exposing asubstrate to at least one preclean process to expose asilicon-containing surface, depositing a metallic silicide material onthe silicon-containing surface during a chemical vapor depositionprocess or an atomic layer deposition process, expose the substrate toan annealing process, depositing a barrier material on the metallicsilicide material, and depositing a tungsten contact material on thebarrier material. The metallic silicide material may contain at leastone element of cobalt, nickel, platinum, palladium, rhodium, alloysthereof, or combinations thereof. The examples provide that thesubstrate, the metallic silicide material, or the barrier material maybe exposed to a silicon-containing reducing gas during a pre-soakprocess or a post-soak process. In some examples, the substrate may beexposed to a plasma treatment during the pre-soak process or thepost-soak process. In one example, a substrate may be optionally exposedto a treatment or a preclean process, a metallic silicide material isdeposited on the substrate, the substrate may be optionally exposed to atreatment, a metallic material or a barrier material may be depositedover the metallic silicide material, and the substrate may be optionallyexposed to a treatment.

Example 1 Cobalt Silicide Material

In one example, a cobalt silicide material may be deposited by a thermalCVD process. Purge gas may be flowed through different portions of thedeposition chamber. At least one purge gas may be flowed throughout thedeposition chamber, such as a bottom purge flowing a purge gas acrossthe bottom the deposition chamber and an edge purge flowing anotherpurge gas across the edge ring. For example, a bottom purge may flowargon having a flow rate of about 1,000 sccm across the bottom thedeposition chamber and an edge purge may flow argon having a flow rateof about 100 sccm across the edge ring.

The substrate may be heated to a temperature within a range from about350° C. to about 550° C. and the ampoule containing the cobalt precursormay be heated to a temperature of about 30° C. The substrate may beexposed to a deposition gas containing a cobalt precursor, a siliconprecursor, hydrogen, and a carrier gas. The cobalt precursor may be acobalt carbonyl compound (e.g., CpCo(CO)₂ or CCTBA), the siliconprecursor may be silane or disilane, and the carrier gas may be argon,nitrogen, hydrogen, or combinations thereof.

The substrate was heated in a deposition chamber to about 400° C. and anampoule containing cobalt precursor CpCo(CO)₂ was heated to about 30° C.An argon carrier gas having a flow rate of about 500 sccm was passedthrough the cobalt precursor to form a cobalt precursor gas. Adeposition gas was formed by combining the cobalt precursor gas withhydrogen gas having a flow rate of about 3,000 sccm and a siliconprecursor gas containing silane having a flow rate of about 1,000 sccmand an argon carrier gas having a flow rate of about 1,000 sccm. Thesubstrate was exposed to the deposition gas for about 5 seconds to forma cobalt silicide layer on the substrate.

The deposition chamber was purged with a gas mixture of argon having aflow rate of about 500 sccm and hydrogen gas having a flow rate of about3,000 sccm for about 2 seconds. Thereafter, the deposition chamber waspurged with hydrogen gas having a flow rate of about 3,000 sccm forabout 2 seconds.

The substrate was exposed to a hydrogen plasma for about 30 seconds. Thehydrogen plasma was formed by flowing hydrogen gas having a flow rate ofabout 3,000 sccm into the deposition chamber and igniting the plasma.The plasma was ignited by a RF generator having a frequency of 350 kHzset with a power output of about 1,200 watts.

The substrate was exposed to a silicon-reducing gas for about 10 secondsduring a soak process. The silicon-reducing gas contained silane havinga flow rate of about 1,000 sccm, argon having a flow rate of about 1,000sccm, and hydrogen having a flow rate of about 3,000 sccm.

Subsequently, the deposition chamber was purged with hydrogen gas havinga flow rate of about 3,000 sccm and argon having a flow rate of about1,000 sccm for about 2 seconds to complete a first cycle. The depositedcobalt silicide layer was about 8 Å thick. The deposition cycle wasrepeated 5 additional times to form a deposited cobalt silicide materialhaving a thickness of about 50 Å thick.

Example 2 Metallic Cobalt Material

In another example, a metallic cobalt material may be deposited by athermal CVD process. Purge gas may be flowed through different portionsof the deposition chamber. At least one purge gas may be flowedthroughout the deposition chamber, such as a bottom purge flowing apurge gas across the bottom the deposition chamber and an edge purgeflowing another purge gas across the edge ring. For example, a bottompurge may flow argon having a flow rate of about 1,000 sccm across thebottom the deposition chamber and an edge purge may flow argon having aflow rate of about 100 sccm across the edge ring.

The substrate may be heated to a temperature within a range from about350° C. to about 550° C. and the ampoule containing the cobalt precursormay be heated to a temperature of about 30° C. The substrate may beexposed to a deposition gas containing a cobalt precursor, hydrogen, anda carrier gas. The cobalt precursor may be a cobalt carbonyl compound(e.g., CpCo(CO)₂ or CCTBA) and the carrier gas may be argon, nitrogen,hydrogen, or combinations thereof.

The substrate was heated in a deposition chamber to about 400° C. and anampoule containing cobalt precursor CpCo(CO)₂ was heated to about 30° C.An argon carrier gas having a flow rate of about 500 sccm was passedthrough the cobalt precursor to form a cobalt precursor gas. Adeposition gas was formed by combining the cobalt precursor gas,hydrogen gas having a flow rate of about 3,000 sccm, and argon having aflow rate of about 1,000 sccm. The substrate was exposed to thedeposition gas for about 5 seconds to form a metallic cobalt layer onthe substrate.

The deposition chamber was purged with a gas mixture of argon having aflow rate of about 500 sccm and hydrogen gas having a flow rate of about3,000 sccm for about 2 seconds. Thereafter, the deposition chamber waspurged with hydrogen gas having a flow rate of about 3,000 sccm forabout 2 seconds.

The substrate was exposed to a hydrogen plasma for about 30 seconds. Thehydrogen plasma was formed by flowing hydrogen gas having a flow rate ofabout 3,000 sccm into the deposition chamber and igniting the plasma.The plasma was ignited by a RF generator having a frequency of 350 kHzset with a power output of about 1,200 watts.

Subsequently, the deposition chamber was purged with hydrogen gas havinga flow rate of about 3,000 sccm and argon having a flow rate of about1,000 sccm for about 2 seconds to complete a first cycle. The depositedmetallic cobalt layer was about 10 Å thick. The deposition cycle wasrepeated 5 additional times to form a deposited metallic cobalt materialhaving a thickness of about 60 Å thick.

Deposition of Metallic Contact Material

FIGS. 17F and 17H illustrate substrate 1700 having contact aperture 1710filled with metallic contact material 1740. Metallic contact material1740 may be deposited during one deposition process or multipleprocesses within steps 1040, 1150, 1250, 1340, 1440, 1550, 1640, or1930. In another embodiment, a metallic contact material may bedeposited during one deposition process or multiple processes withinsteps 2440 or 2650. Metallic contact material 1740 may contain copper,tungsten, aluminum, or an alloy thereof and may be formed using one ormore suitable deposition processes. In one embodiment, for example,metallic contact material 1740 may contain a seed layer and a bulk layerformed on cobalt silicide material 1720 or metallic cobalt material 1730by using one or more deposition process that include a CVD process, anALD process, a PVD process, an electroless deposition process, anelectrochemical plating (ECP) process, a derivative thereof or acombination thereof. Substrate 1700 may be exposed to pretreatmentprocess, such as a soaking process, prior to depositing cobalt silicidematerial 1720 or metallic cobalt material 1730, as well as prior todepositing metallic contact material 1740, including a pre-nucleationsoak process to cobalt silicide material 1720 or metallic cobaltmaterial 1730 and a post-nucleation soak process to a seed layer.Further disclosure of processes for depositing a tungsten material on atransition metal seed layer is further described in commonly assignedand co-pending U.S. Ser. No. 11/009,331, filed Dec. 10, 2004, andpublished as US 2006-0128150, which is herein incorporated by referencein its entirety.

In one embodiment, metallic contact material 1740 preferably containscopper or a copper alloy. For example, a copper seed layer may be formedon cobalt silicide material 1720 or metallic cobalt material 1730 by aCVD process and thereafter, bulk copper is deposited to fill theinterconnect by an ECP process. In another example, a copper seed layermay be formed on cobalt silicide material 1720 or metallic cobaltmaterial 1730 by a PVD process and thereafter, bulk copper is depositedto fill the interconnect by an ECP process. In another example, a copperseed layer may be formed on cobalt silicide material 1720 or metalliccobalt material 1730 by an electroless process and thereafter, bulkcopper is deposited to fill the interconnect by an ECP process. Inanother example, cobalt silicide material 1720 or metallic cobaltmaterial 1730 serves as a seed layer to which a copper bulk fill isdirectly deposited by an ECP process or an electroless depositionprocess.

In another embodiment, metallic contact material 1740 preferablycontains tungsten or a tungsten alloy. For example, a tungsten seedlayer may be formed on cobalt silicide material 1720 or metallic cobaltmaterial 1730 by an ALD process and thereafter, bulk tungsten isdeposited to fill the interconnect by a CVD process or a pulsed-CVDprocess. In another example, a tungsten seed layer may be formed oncobalt silicide material 1720 or metallic cobalt material 1730 by a PVDprocess and thereafter, bulk tungsten is deposited to fill theinterconnect by a CVD process or a pulsed-CVD process. In anotherexample, a tungsten seed layer may be formed on cobalt silicide material1720 or metallic cobalt material 1730 by an ALD process and thereafter,bulk tungsten is deposited to fill the interconnect by an ECP process.In another example, cobalt silicide material 1720 or metallic cobaltmaterial 1730 serves as a seed layer to which a tungsten bulk fill isdirectly deposited by a CVD process or a pulsed-CVD process.

In another embodiment, metallic contact material 1740 preferablycontains a tungsten nitride material and a metallic tungsten material ora tungsten alloy. A tungsten nitride layer may be deposited on cobaltsilicide material 1720 or metallic cobalt material 1730, thereafter, atleast one tungsten material may be deposited on the tungsten nitridelayer, such as a tungsten seed layer and a bulk tungsten layer. Forexample, a tungsten nitride layer may be formed on cobalt silicidematerial 1720 or metallic cobalt material 1730 by an ALD process, atungsten seed layer may be formed on the tungsten nitride layer by anALD process, and thereafter, bulk tungsten is deposited to fill theinterconnect by a CVD process or a pulsed-CVD process. In anotherexample, a tungsten nitride layer may be formed on cobalt silicidematerial 1720 or metallic cobalt material 1730 by a PVD process, atungsten seed layer may be formed on the tungsten nitride layer by anALD process, and thereafter, bulk tungsten is deposited to fill theinterconnect by a CVD process or a pulsed-CVD process. In anotherexample, a tungsten nitride layer may be formed on cobalt silicidematerial 1720 or metallic cobalt material 1730 by an ALD process, atungsten seed layer may be formed on the tungsten nitride layer by a PVDprocess, and thereafter, bulk tungsten is deposited to fill theinterconnect by a CVD process or a pulsed-CVD process.

In another example, a tungsten nitride layer may be formed on cobaltsilicide material 1720 or metallic cobalt material 1730 by a PVDprocess, a tungsten seed layer may be formed on the tungsten nitridelayer by an ALD process, and thereafter, bulk tungsten is deposited tofill the interconnect by an ECP process. In another example, a tungstennitride layer may be formed on cobalt silicide material 1720 or metalliccobalt material 1730 by an ALD process, a tungsten seed layer may beformed on the tungsten nitride layer by a PVD process, and thereafter,bulk tungsten is deposited to fill the interconnect by an ECP process.In another example, the tungsten nitride layer may be deposited by anALD process or a PVD process and a tungsten bulk fill is directlydeposited to the tungsten nitride layer by a CVD process or a pulsed-CVDprocess.

In one embodiment, processing platform system 1835 contains a pluralityof processing chambers 1836, 1838, 1840, 1841, 1842, and 1843, disposedon transfer chambers 1848 and 1850, as depicted in FIG. 18. In oneexample, processing chamber 1836 is a CVD chamber for depositing acobalt silicide material, processing chamber 1838 is a CVD chamber fordepositing a metallic cobalt material, processing chamber 1840 is an ALDchamber for depositing a barrier layer (e.g., Ta/TaN), processingchamber 1841 is an ALD chamber for depositing a tungsten nucleationlayer, processing chamber 1842 is a preclean chamber, processing chamber1843 is a CVD chamber for depositing a tungsten bulk layer. An annealingprocess may be done in any of processing chambers 1836, 1838, 1840,1841, 1842, or 1843. The substrates may be transferred betweenprocessing chambers 1836, 1838, 1840, 1841, 1842, and 1843 withinprocessing platform system 1835 without breaking a vacuum or exposingthe substrates to other external environmental conditions.

In another example, processing chamber 1836 is an annealing chamber forannealing the substrate, processing chamber 1838 is a CVD chamber fordepositing a cobalt silicide material and a metallic cobalt material,processing chamber 1840 is a PVD chamber for depositing a barrier layer(e.g., Ti/TiN), processing chamber 1841 is an ALD chamber for depositinga tungsten nucleation layer, processing chamber 1842 is a precleanchamber, processing chamber 1843 is a CVD chamber for depositing atungsten bulk layer. An annealing process may be done in any ofprocessing chambers 1836, 1838, 1840, 1841, 1842, or 1843.

In another example, processing chamber 1836 is an annealing chamber forannealing the substrate, processing chamber 1838 is a CVD chamber fordepositing a cobalt silicide material and a metallic cobalt material,processing chamber 1840 is a PVD chamber for depositing a barrier layer(e.g., Ta/TaN), processing chamber 1841 is a PVD chamber for depositinga copper nucleation layer, processing chamber 1842 is a precleanchamber, processing chamber 1843 is an electroless deposition chamberfor depositing a copper bulk layer. An annealing process may be done inany of processing chambers 1836, 1838, 1840, 1841, 1842, or 1843.

In another example, processing chamber 1836 is an annealing chamber forannealing the substrate, processing chamber 1838 is a CVD chamber fordepositing a cobalt silicide material and a metallic cobalt material,processing chamber 1840 is an ALD chamber for depositing a barrier layer(e.g., Ta/TaN), processing chamber 1841 is an ALD chamber for depositinga ruthenium nucleation layer, processing chamber 1842 is a precleanchamber, processing chamber 1843 is an electroless deposition chamberfor depositing a copper bulk layer. An annealing process may be done inany of processing chambers 1836, 1838, 1840, 1841, 1842, or 1843.

In another example, processing chamber 1836 is an ALD chamber fordepositing a cobalt silicide material, processing chamber 1838 is a CVDchamber for depositing a metallic cobalt material, processing chamber1840 is an ALD chamber for depositing a barrier layer (e.g., Ta/TaN),processing chamber 1841 is an ALD chamber for depositing a rutheniumnucleation layer, processing chamber 1842 is a preclean chamber,processing chamber 1843 is an electroless deposition chamber fordepositing a copper bulk layer. An annealing process may be done in anyof processing chambers 1836, 1838, 1840, 1841, 1842, or 1843.

Annealing Process

In one embodiment, substrate 1700 or other substrates may be exposed toat least one annealing process during steps 1140, 1230, 1360, 1450,1530, 1630, or 2630. In other embodiments, substrate 1700 may be exposedan annealing process prior to, during, or subsequently to the depositionof cobalt silicide materials, metallic cobalt materials, other cobaltcontaining materials, or metallic contact materials. In one embodiment,substrate 1700 may be transferred to an annealing chamber, such as theCENTURA® RADIANCE® RTP chamber or a rapid thermal annealing (RTA)chamber, both available from Applied Materials, Inc., located in SantaClara, Calif., and exposed to the thermal annealing process. Theannealing chamber may be on the same cluster tool as the depositionchamber and/or the nitridation chamber, such that substrate 1700 may beannealed without being exposed to the ambient environment. In oneembodiment, degas chambers 1844 may be used during the annealingprocesses. In another embodiment, chambers 1836 and 1842 may be usedduring the annealing processes.

Substrate 1700 may be heated to a temperature within a range from about600° C. to about 1,200° C., preferably, from about 700° C. to about1,150° C., and more preferably, from about 800° C. to about 1,000° C.The thermal annealing process may last for a time period within a rangefrom about 1 second to about 120 seconds, preferably, from about 2seconds to about 60 seconds, and more preferably, from about 5 secondsto about 30 seconds. Generally, the chamber atmosphere contains at leastone annealing gas, such as nitrogen, hydrogen, argon, helium, forminggas, derivatives thereof, or combinations thereof. The process chambermay have a pressure within a range from about 5 Torr to about 100 Torr,for example, about 10 Torr. In one example of a thermal annealingprocess, substrate 1700 is heated to a temperature of about 1,050° C.for about 15 seconds within an inert atmosphere. In another example,substrate 1700 is heated to a temperature of about 1,100° C. for about25 seconds within an inert atmosphere.

In one embodiment, the thermal annealing process converts metalliccobalt material 1715 to cobalt silicide material 1720, as depicted inFIGS. 17C-17D. In one example, a cobalt silicide material may have afilm thickness within a range from about 1 Å to about 200 Å, preferablyfrom about 3 Å to about 80 Å, and more preferably from about 5 Å toabout 30 Å. In another example, a metallic cobalt material may have afilm thickness within a range from about 1 Å to about 300 Å, preferably,from about 5 Å to about 100 Å, and more preferably, from about 10 Å toabout 50 Å.

In another embodiment, substrate 1700 may be exposed to at least oneplasma annealing process during steps 1140, 1230, 1360, 1450, 1530, or1630. In other embodiments, substrate 1700 may be exposed a plasmaannealing process prior to, during, or subsequently to the deposition ofcobalt silicide materials, metallic cobalt materials, other cobaltcontaining materials, or metallic contact materials. The plasma may begenerated in situ the processing chamber or may be generated remotelyand delivered into the processing, such as by a RPS. The plasma chambermay be on the same cluster tool as the deposition chamber and/or thenitridation chamber, such that substrate 1700 may be annealed withoutbeing exposed to the ambient environment. In one embodiment, chambers1836 and 1842 may be used during the plasma annealing processes.

Etching or Planarization Process

In one embodiment, substrate 1700 may be exposed to at least one etchingprocess or planarization process during steps 1050, 1160, 1260, 1350,1460, 1560, 1650, 1940, or 2660 to remove materials from substrate field1745 of substrate 1700, as depicted in FIG. 17G. A portion of thedeposited material of cobalt silicide material 1720, metallic cobaltmaterial 1730, metallic contact material 1740, other cobalt containingmaterials, or metallic contact materials. Etching processes include wetor dry etching processes, such as etch-back processes available fromApplied Materials, Inc., located in Santa Clara, Calif. Planarizationprocesses may include mechanical polishing, chemical mechanicalpolishing (CMP), electro-CMP (ECMP), reactive ion etching (RIE), orother known techniques used to planarize substrates. Specific processesand compositions are predetermined and may vary based on the compositionof metallic contact material 1740 (e.g., Cu, W, Al, or alloys thereof).A further description of planarization processes that may be used duringembodiments herein are further disclosed in commonly assigned U.S. Ser.No. 10/948,958 (APPM/9038), filed Sep. 24, 2004, and published asUS-2006-0021974, and commonly assigned U.S. Ser. No. 11/130,032(APPM/9038.P1), filed May 16, 2005, and published as US 2005-0233578,which are herein incorporated by reference in their entirety.

Barrier Layer Deposition

In an alternative embodiment, a barrier layer may be formed on metalliccobalt material 1730 prior to depositing metallic contact material 1740.The barrier layer may be deposited after step 1030 and before step 1040of process 1000, after step 1130 and before step 1150 of process 1100,after step 1240 and before step 1250 of process 1200, after step 1330and before step 1340 of process 1300, after step 1430 and before step1440 of process 1400, after step 1540 and before step 1550 of process1500, after step 1620 and before step 1640 of process 1600. In anotheralternative embodiment, a barrier layer may be formed on cobalt silicidematerial 1720 prior to depositing metallic contact material 1740. Inanother embodiment, the barrier layer may be deposited after step 1920and before step 1930 during process 1900. In another embodiment, thebarrier layer may be deposited in step 2640 during process 2600.

The barrier layer may include one or more barrier materials such as, forexample, tantalum, tantalum nitride, tantalum silicon nitride, titanium,titanium nitride, titanium silicon nitride, tungsten, tungsten nitride,silicon nitride, ruthenium, derivatives thereof, alloys thereof, orcombinations thereof. In some embodiments, the barrier material maycontain cobalt or cobalt silicide. The barrier layer may beformed/deposited using a suitable deposition process, such as ALD, CVD,PVD, or electroless deposition. For example, tantalum nitride may bedeposited using a CVD process or an ALD process whereintantalum-containing compound or tantalum precursor (e.g., PDMAT) andnitrogen-containing compound or nitrogen precursor (e.g., ammonia) arereacted. In one embodiment, tantalum and/or tantalum nitride isdeposited as a barrier layer by an ALD process as described in commonlyassigned U.S. Ser. No. 10/281,079, entitled “Gas Delivery Apparatus forAtomic Layer Deposition,” filed Oct. 25, 2002, and published as US2003-0121608, which is herein incorporated by reference. In one example,a Ta/TaN bilayer may be deposited as a barrier layer material, such as ametallic tantalum layer and a tantalum nitride layer that areindependently deposited by ALD, CVD, and/or PVD processes, one layer ontop of the other layer, in either order. In another example, a Ti/TiNbilayer may be deposited as a barrier layer material, such as a metallictitanium layer and a titanium nitride layer that are independentlydeposited by ALD, CVD, and/or PVD processes, one layer on top of theother layer, in either order. In another example, a W/WN bilayer may bedeposited as a barrier layer material, such as a metallic tungsten layerand a tungsten nitride layer that are independently deposited by ALD,CVD, and/or PVD processes, one layer on top of the other layer, ineither order.

“Substrate surface” or “substrate,” as used herein, refers to anysubstrate or material surface formed on a substrate upon which filmprocessing is performed during a fabrication process. For example, asubstrate surface on which processing may be performed include materialssuch as monocrystalline, polycrystalline or amorphous silicon, strainedsilicon, silicon on insulator (SOI), doped silicon, silicon germanium,germanium, gallium arsenide, glass, sapphire, silicon oxide, siliconnitride, silicon oxynitride, and/or carbon doped silicon oxides, such asSiO_(x)C_(y), for example, BLACK DIAMOND® low-k dielectric, availablefrom Applied Materials, Inc., located in Santa Clara, Calif. Substratesmay have various dimensions, such as 200 mm or 300 mm diameter wafers,as well as, rectangular or square panes. Unless otherwise noted,embodiments and examples described herein are preferably conducted onsubstrates with a 200 mm diameter or a 300 mm diameter, more preferably,a 300 mm diameter. Embodiments of the processes described herein depositcobalt silicide materials, metallic cobalt materials, and othercobalt-containing materials on many substrates and surfaces, especially,silicon-containing dielectric materials. Substrates on which embodimentsof the invention may be useful include, but are not limited tosemiconductor wafers, such as crystalline silicon (e.g., Si<100> orSi<111>), silicon oxide, strained silicon, silicon germanium, doped orundoped polysilicon, doped or undoped silicon wafers, and patterned ornon-patterned wafers. Substrates may be exposed to a pretreatmentprocess to polish, etch, reduce, oxidize, hydroxylate, anneal, and/orbake the substrate surface.

“Atomic layer deposition” or “cyclical deposition” as used herein refersto the sequential introduction of two or more reactive compounds todeposit a layer of material on a substrate surface. The two, three ormore reactive compounds may alternatively be introduced into a reactionzone of a process chamber. Usually, each reactive compound is separatedby a time delay to allow each compound to adhere and/or react on thesubstrate surface. In one aspect, a first precursor or compound A ispulsed into the reaction zone followed by a first time delay. Next, asecond precursor or compound B is pulsed into the reaction zone followedby a second delay. During each time delay a purge gas, such as nitrogen,is introduced into the process chamber to purge the reaction zone orotherwise remove any residual reactive compound or by-products from thereaction zone. Alternatively, the purge gas may flow continuouslythroughout the deposition process so that only the purge gas flowsduring the time delay between pulses of reactive compounds. Inalternative embodiments, the purge gas may also be a reducing agent,such as hydrogen or silane. The reactive compounds are alternativelypulsed until a desired film or film thickness is formed on the substratesurface. In either scenario, the ALD process of pulsing compound A,purge gas, pulsing compound B and purge gas is a cycle. A cycle canstart with either compound A or compound B and continue the respectiveorder of the cycle until achieving a film with the desired thickness. Inanother embodiment, a first precursor containing compound A, a secondprecursor containing compound B, and a third precursor containingcompound C are each separately and alternatively pulsed into the processchamber. Alternatively, a first precursor containing compound A and asecond precursor containing compound B are each separately andalternatively pulsed into the process chamber while, and a thirdprecursor containing compound C is continuously flowed into the processchamber. Alternatively, a pulse of a first precursor may overlap in timewith a pulse of a second precursor while a pulse of a third precursordoes not overlap in time with either pulse of the first and secondprecursors.

A “pulse” as used herein is intended to refer to a quantity of aparticular compound that is intermittently or non-continuouslyintroduced into a reaction zone of a processing chamber. The quantity ofa particular compound within each pulse may vary over time, depending onthe duration of the pulse. The duration of each pulse is variabledepending upon a number of factors such as, for example, the volumecapacity of the process chamber employed, the vacuum system coupledthereto, and the volatility/reactivity of the particular compounditself. A “half-reaction” as used herein to refer to a pulse of aprecursor followed by a purge step.

While the foregoing is directed to embodiments of the invention, otherand further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A method of forming a copper material on a substrate, sequentiallycomprising: exposing the substrate to a first argon plasma during aplasma cleaning process; depositing a tantalum nitride layer over thesubstrate by physical vapor deposition; exposing the tantalum nitridelayer to a plasma comprising argon and hydrogen during a plasmatreatment process; depositing a cobalt layer having a thickness within arange from about 10 angstroms to about 100 angstroms over the substrateduring a chemical vapor deposition process, wherein the substrate isexposed to dicobalt hexacarbonyl butylacetylene or cyclopentadienylcobalt bis(carbonyl) during the chemical vapor deposition process;exposing the cobalt layer to a second argon plasma; and depositing acopper layer over the substrate during an electrochemical platingprocess.
 2. The method of claim 1, further comprising performing anetching process after the depositing a copper layer.
 3. The method ofclaim 1, wherein the first argon plasma is generated at a power settingbetween about 500 watts and about 2000 watts.
 4. The method of claim 3,wherein the cobalt layer has a thickness within a range from about 40angstroms to about 50 angstroms.
 5. (canceled)
 6. The method of claim 1,further comprising depositing a tantalum layer prior to depositing thetantalum nitride layer.
 7. The method of claim 6, wherein the depositinga copper layer comprises: depositing a copper seed layer by physicalvapor deposition; and depositing a copper bulk layer on the copper seedlayer by electrochemical plating.
 8. The method of claim 1, wherein theexposing the substrate to the first argon plasma comprises cyclicallygenerating a plasma from argon and purging the argon from a processchamber.
 9. A method of forming a copper material on a substrate,sequentially comprising: exposing the substrate to a first argon plasma;depositing a tantalum nitride layer over the substrate by atomic layerdeposition, wherein the tantalum nitride layer is formed by reactingpentakis(dimethylamino)tantalum and a nitrogen-containing precursor;exposing the tantalum nitride layer to a plasma comprising argon andhydrogen during a plasma treatment process; depositing a cobalt layerhaving a thickness within a range from about 20 angstroms to about 70angstroms over the substrate during a chemical vapor deposition process,wherein the substrate is exposed to dicobalt hexacarbonyl butylacetyleneduring the chemical vapor deposition process, and wherein the depositinga cobalt layer comprises cyclically depositing cobalt and exposing thedeposited cobalt to argon plasma; and depositing a copper layer over thesubstrate during an electrochemical plating process.
 10. (canceled) 11.The method of claim 9, wherein depositing the copper layer comprises:depositing a copper seed layer by physical vapor deposition; anddepositing a copper bulk layer on the copper seed layer byelectrochemical plating.
 12. The method of claim 9, further comprisingperforming an etching process after the depositing a copper layer. 13.The method of claim 9, wherein the nitrogen-containing precursor isammonia.
 14. The method of claim 9, wherein the substrate is exposed tothe first argon plasma for about 30 seconds to about 4 minutes, andwherein the plasma is generated at a power setting between about 900watts and about 1800 watts.
 15. A method of forming a copper material ona substrate, sequentially comprising: exposing the substrate to a firstargon plasma; depositing a tantalum nitride layer over the substrate byatomic layer deposition, wherein the tantalum nitride layer is formed byreacting pentakis(dimethylamino)tantalum and a nitrogen-containingprecursor; exposing the tantalum nitride layer to a plasma comprisingargon and hydrogen during a plasma treatment process; depositing acobalt layer having a thickness within a range from about 20 angstromsto about 70 angstroms over the substrate during a plasma-enhancedchemical vapor deposition process, wherein the substrate is exposed todicobalt hexacarbonyl butylacetylene during the plasma enhanced chemicalvapor deposition process; and depositing a copper layer over thesubstrate during an electrochemical plating process.
 16. The method ofclaim 15, wherein depositing the copper layer comprises: depositing acopper seed layer by physical vapor deposition; and depositing a copperbulk layer on the copper seed layer by electrochemical plating.
 17. Themethod of claim 15, further comprising depositing a tantalum layer priorto depositing the tantalum nitride layer.
 18. The method of claim 15,further comprising performing an etching process after the depositing acopper layer.